From 760a171903e0fe314b6795669893850bf46cad78 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Tue, 11 Aug 2020 09:14:13 -0500
Subject: [PATCH 01/19] nrf: Make port build with -Werror=undef

.. build-tested on particle_xenon
---
 ports/nrf/Makefile                | 16 +++++++++-------
 ports/nrf/common-hal/busio/SPI.c  | 16 ++++++++++++++++
 ports/nrf/supervisor/qspi_flash.c |  2 +-
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/ports/nrf/Makefile b/ports/nrf/Makefile
index 13a148df3b..d1745a70ef 100755
--- a/ports/nrf/Makefile
+++ b/ports/nrf/Makefile
@@ -73,11 +73,11 @@ INC += -I$(BUILD)
 INC += -I$(BUILD)/genhdr
 INC += -I./../../lib/cmsis/inc
 INC += -I./boards/$(BOARD)
-INC += -I./nrfx
-INC += -I./nrfx/hal
-INC += -I./nrfx/mdk
-INC += -I./nrfx/drivers/include
-INC += -I./nrfx/drivers/src
+INC += -isystem ./nrfx
+INC += -isystem ./nrfx/hal
+INC += -isystem ./nrfx/mdk
+INC += -isystem ./nrfx/drivers/include
+INC += -isystem ./nrfx/drivers/src
 INC += -I./bluetooth
 INC += -I./peripherals
 INC += -I../../lib/mp-readline
@@ -100,8 +100,8 @@ CFLAGS += $(OPTIMIZATION_FLAGS)
 CFLAGS += $(INC) -Wall -Werror -std=gnu11 -nostdlib -fshort-enums $(BASE_CFLAGS) $(CFLAGS_MOD) $(COPT)
 
 # Undo some warnings.
-# nrfx uses undefined preprocessor variables quite casually, so we can't do warning checks for these.
-CFLAGS += -Wno-undef
+## nrfx uses undefined preprocessor variables quite casually, so we can't do warning checks for these.
+#CFLAGS += -Wno-undef
 # nrfx does casts that increase alignment requirements.
 CFLAGS += -Wno-cast-align
 
@@ -240,6 +240,8 @@ endif
 OBJ += $(addprefix $(BUILD)/, $(SRC_S:.s=.o))
 OBJ += $(addprefix $(BUILD)/, $(SRC_MOD:.c=.o))
 
+$(addprefix $(BUILD)/, $(SRC_NRFX:.c=.o)): CFLAGS += -Wno-undef
+
 $(BUILD)/$(FATFS_DIR)/ff.o: COPT += -Os
 $(filter $(PY_BUILD)/../extmod/vfs_fat_%.o, $(PY_O)): COPT += -Os
 
diff --git a/ports/nrf/common-hal/busio/SPI.c b/ports/nrf/common-hal/busio/SPI.c
index f27f0e267b..fdfe61811b 100644
--- a/ports/nrf/common-hal/busio/SPI.c
+++ b/ports/nrf/common-hal/busio/SPI.c
@@ -34,6 +34,22 @@
 #include "nrfx_spim.h"
 #include "nrf_gpio.h"
 
+#ifndef NRFX_SPIM3_ENABLED
+#define NRFX_SPIM3_ENABLED (0)
+#endif
+
+#ifndef NRFX_SPIM2_ENABLED
+#define NRFX_SPIM2_ENABLED (0)
+#endif
+
+#ifndef NRFX_SPIM1_ENABLED
+#define NRFX_SPIM1_ENABLED (0)
+#endif
+
+#ifndef NRFX_SPIM0_ENABLED
+#define NRFX_SPIM0_ENABLED (0)
+#endif
+
 // These are in order from highest available frequency to lowest (32MHz first, then 8MHz).
 STATIC spim_peripheral_t spim_peripherals[] = {
 #if NRFX_CHECK(NRFX_SPIM3_ENABLED)
diff --git a/ports/nrf/supervisor/qspi_flash.c b/ports/nrf/supervisor/qspi_flash.c
index 5ab56c6bc4..7ca27d56c4 100644
--- a/ports/nrf/supervisor/qspi_flash.c
+++ b/ports/nrf/supervisor/qspi_flash.c
@@ -201,7 +201,7 @@ void spi_flash_init(void) {
         .irq_priority = 7,
     };
 
-#if EXTERNAL_FLASH_QSPI_DUAL
+#if defined(EXTERNAL_FLASH_QSPI_DUAL)
     qspi_cfg.pins.io1_pin = MICROPY_QSPI_DATA1;
     qspi_cfg.prot_if.readoc = NRF_QSPI_READOC_READ2O;
     qspi_cfg.prot_if.writeoc = NRF_QSPI_WRITEOC_PP2O;

From 32fc8b0676eac575a184f529aae6848f189ea71a Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Tue, 11 Aug 2020 14:16:05 -0500
Subject: [PATCH 02/19] nrf: reset_pin_number: reset pin clears never-reset,
 mirroring samd

---
 ports/nrf/common-hal/microcontroller/Pin.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ports/nrf/common-hal/microcontroller/Pin.c b/ports/nrf/common-hal/microcontroller/Pin.c
index 3132c76318..d294c1dd5d 100644
--- a/ports/nrf/common-hal/microcontroller/Pin.c
+++ b/ports/nrf/common-hal/microcontroller/Pin.c
@@ -93,6 +93,7 @@ void reset_pin_number(uint8_t pin_number) {
 
     // Clear claimed bit.
     claimed_pins[nrf_pin_port(pin_number)] &= ~(1 << nrf_relative_pin_number(pin_number));
+    never_reset_pins[nrf_pin_port(pin_number)] &= ~(1 << nrf_relative_pin_number(pin_number));
 
     #ifdef MICROPY_HW_NEOPIXEL
     if (pin_number == MICROPY_HW_NEOPIXEL->number) {

From ffc488e748890976fe1923c5503300f66064d904 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Fri, 31 Jul 2020 14:34:24 -0500
Subject: [PATCH 03/19] framebufferio: Fix crash calling unimplemented
 get_brightness

If set_brightness was implemented but get_brightness wasn't, this
would hard fault
---
 shared-module/framebufferio/FramebufferDisplay.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/shared-module/framebufferio/FramebufferDisplay.c b/shared-module/framebufferio/FramebufferDisplay.c
index 2a90fa0d4a..73917b1a32 100644
--- a/shared-module/framebufferio/FramebufferDisplay.c
+++ b/shared-module/framebufferio/FramebufferDisplay.c
@@ -109,7 +109,7 @@ bool common_hal_framebufferio_framebufferdisplay_set_auto_brightness(framebuffer
 }
 
 mp_float_t common_hal_framebufferio_framebufferdisplay_get_brightness(framebufferio_framebufferdisplay_obj_t* self) {
-    if (self->framebuffer_protocol->set_brightness) {
+    if (self->framebuffer_protocol->get_brightness) {
         return self->framebuffer_protocol->get_brightness(self->framebuffer);
     }
     return -1;

From 5a7b2a20381513797b4e548684f8af5af46be0fa Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Fri, 31 Jul 2020 14:35:00 -0500
Subject: [PATCH 04/19] framebufferio: Don't call swapbuffers unnecessarily

---
 shared-module/framebufferio/FramebufferDisplay.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/shared-module/framebufferio/FramebufferDisplay.c b/shared-module/framebufferio/FramebufferDisplay.c
index 73917b1a32..fed3352aa0 100644
--- a/shared-module/framebufferio/FramebufferDisplay.c
+++ b/shared-module/framebufferio/FramebufferDisplay.c
@@ -219,12 +219,14 @@ STATIC void _refresh_display(framebufferio_framebufferdisplay_obj_t* self) {
     displayio_display_core_start_refresh(&self->core);
     self->framebuffer_protocol->get_bufinfo(self->framebuffer, &self->bufinfo);
     const displayio_area_t* current_area = _get_refresh_areas(self);
-    while (current_area != NULL) {
-        _refresh_area(self, current_area);
-        current_area = current_area->next;
+    if (current_area) {
+        while (current_area != NULL) {
+            _refresh_area(self, current_area);
+            current_area = current_area->next;
+        }
+        self->framebuffer_protocol->swapbuffers(self->framebuffer);
     }
     displayio_display_core_finish_refresh(&self->core);
-    self->framebuffer_protocol->swapbuffers(self->framebuffer);
 }
 
 void common_hal_framebufferio_framebufferdisplay_set_rotation(framebufferio_framebufferdisplay_obj_t* self, int rotation){

From 6d19a098888236c7442e563bae90b09630fbefe2 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Fri, 31 Jul 2020 14:35:50 -0500
Subject: [PATCH 05/19] framebufferio: Set type to none when releasing

This avoids the message "Too many displays in use" when they are released
directly, rather than via release_displays().
---
 shared-module/framebufferio/FramebufferDisplay.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/shared-module/framebufferio/FramebufferDisplay.c b/shared-module/framebufferio/FramebufferDisplay.c
index fed3352aa0..d21a103e2a 100644
--- a/shared-module/framebufferio/FramebufferDisplay.c
+++ b/shared-module/framebufferio/FramebufferDisplay.c
@@ -309,6 +309,7 @@ void release_framebufferdisplay(framebufferio_framebufferdisplay_obj_t* self) {
     common_hal_framebufferio_framebufferdisplay_set_auto_refresh(self, false);
     release_display_core(&self->core);
     self->framebuffer_protocol->deinit(self->framebuffer);
+    self->base.type = &mp_type_NoneType;
 }
 
 void reset_framebufferdisplay(framebufferio_framebufferdisplay_obj_t* self) {

From a84cc19499e1cb71387cb5be379676d0c8b84f9a Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Fri, 31 Jul 2020 15:46:07 -0500
Subject: [PATCH 06/19] framebufferio: Handle 1 (tested), 2, and 4 bpp displays

---
 .../framebufferio/FramebufferDisplay.c        | 20 +++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/shared-module/framebufferio/FramebufferDisplay.c b/shared-module/framebufferio/FramebufferDisplay.c
index d21a103e2a..b007975377 100644
--- a/shared-module/framebufferio/FramebufferDisplay.c
+++ b/shared-module/framebufferio/FramebufferDisplay.c
@@ -147,6 +147,14 @@ STATIC bool _refresh_area(framebufferio_framebufferdisplay_obj_t* self, const di
         return true;
     }
     uint16_t subrectangles = 1;
+
+    // If pixels are packed by row then rows are on byte boundaries
+    if (self->core.colorspace.depth < 8 && self->core.colorspace.pixels_in_byte_share_row) {
+        int div = 8 / self->core.colorspace.depth;
+        clipped.x1 = (clipped.x1 / div) * div;
+        clipped.x2 = ((clipped.x2 + div - 1) / div) * div;
+    }
+
     uint16_t rows_per_buffer = displayio_area_height(&clipped);
     uint8_t pixels_per_word = (sizeof(uint32_t) * 8) / self->core.colorspace.depth;
     uint16_t pixels_per_buffer = displayio_area_size(&clipped);
@@ -187,6 +195,7 @@ STATIC bool _refresh_area(framebufferio_framebufferdisplay_obj_t* self, const di
             .x2 = clipped.x2,
             .y2 = clipped.y1 + rows_per_buffer * (j + 1)
         };
+
         if (remaining_rows < rows_per_buffer) {
             subrectangle.y2 = subrectangle.y1 + remaining_rows;
         }
@@ -197,12 +206,15 @@ STATIC bool _refresh_area(framebufferio_framebufferdisplay_obj_t* self, const di
 
         displayio_display_core_fill_area(&self->core, &subrectangle, mask, buffer);
 
-        // COULDDO: this arithmetic only supports multiple-of-8 bpp
-        uint8_t *dest = self->bufinfo.buf + (subrectangle.y1 * self->core.width + subrectangle.x1) * (self->core.colorspace.depth / 8);
+        uint8_t *buf = (uint8_t *)self->bufinfo.buf, *endbuf = buf + self->bufinfo.len;
+        (void)endbuf; // Hint to compiler that endbuf is "used" even if NDEBUG
+
+        uint8_t *dest = self->bufinfo.buf + (subrectangle.y1 * self->core.width + subrectangle.x1) * self->core.colorspace.depth / 8;
         uint8_t *src = (uint8_t*)buffer;
-        size_t rowsize = (subrectangle.x2 - subrectangle.x1) * (self->core.colorspace.depth / 8);
-        size_t rowstride = self->core.width * (self->core.colorspace.depth/8);
+        size_t rowsize = (subrectangle.x2 - subrectangle.x1) * self->core.colorspace.depth / 8;
+        size_t rowstride = self->core.width * self->core.colorspace.depth/8;
         for (uint16_t i = subrectangle.y1; i < subrectangle.y2; i++) {
+            assert(dest >= buf && dest < endbuf && dest+rowsize <= endbuf);
             memcpy(dest, src, rowsize);
             dest += rowstride;
             src += rowsize;

From 8021f3b4cbb96e0edaf139fa88ea7273c92a5493 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Fri, 31 Jul 2020 15:46:39 -0500
Subject: [PATCH 07/19] framebufferio: handle sharp memory displays

A bit of cheating; we need to add a protocol getter for
reverse_bytes_in_word
---
 shared-module/framebufferio/FramebufferDisplay.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/shared-module/framebufferio/FramebufferDisplay.c b/shared-module/framebufferio/FramebufferDisplay.c
index b007975377..190d3cb9dc 100644
--- a/shared-module/framebufferio/FramebufferDisplay.c
+++ b/shared-module/framebufferio/FramebufferDisplay.c
@@ -51,7 +51,7 @@ void common_hal_framebufferio_framebufferdisplay_construct(framebufferio_framebu
 
     uint16_t ram_width = 0x100;
     uint16_t ram_height = 0x100;
-
+    uint16_t depth = self->framebuffer_protocol->get_color_depth(self->framebuffer);
     displayio_display_core_construct(
         &self->core,
         NULL,
@@ -62,12 +62,13 @@ void common_hal_framebufferio_framebufferdisplay_construct(framebufferio_framebu
         0,
         0,
         rotation,
-        self->framebuffer_protocol->get_color_depth(self->framebuffer),
-        false,
-        false,
+        depth,
+        (depth < 12), // grayscale
+        true, // pixels_in_byte_share_row
         self->framebuffer_protocol->get_bytes_per_cell(self->framebuffer),
-        false,
-        false);
+        true, // reverse_pixels_in_byte
+        false // reverse_bytes_in_word
+    );
 
     self->first_manual_refresh = !auto_refresh;
 

From a33e48c065093212729e620bb22da5ca327fabe4 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Thu, 6 Aug 2020 14:28:10 -0500
Subject: [PATCH 08/19] framebufferio: add "first pixel offset" and "row
 stride"

---
 .../framebufferio/FramebufferDisplay.c          | 17 ++++++++++++++---
 .../framebufferio/FramebufferDisplay.h          |  5 +++++
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/shared-module/framebufferio/FramebufferDisplay.c b/shared-module/framebufferio/FramebufferDisplay.c
index 190d3cb9dc..e16777b83b 100644
--- a/shared-module/framebufferio/FramebufferDisplay.c
+++ b/shared-module/framebufferio/FramebufferDisplay.c
@@ -70,6 +70,15 @@ void common_hal_framebufferio_framebufferdisplay_construct(framebufferio_framebu
         false // reverse_bytes_in_word
     );
 
+    self->first_pixel_offset = self->framebuffer_protocol->get_first_pixel_offset
+        ? self->framebuffer_protocol->get_first_pixel_offset(self->framebuffer)
+        : 0;
+    self->row_stride = self->framebuffer_protocol->get_row_stride
+        ? self->framebuffer_protocol->get_row_stride(self->framebuffer)
+        : 0;
+    if (self->row_stride == 0) {
+        self->row_stride = self->core.width * self->core.colorspace.depth/8;
+    }
     self->first_manual_refresh = !auto_refresh;
 
     self->native_frames_per_second = self->framebuffer_protocol->get_native_frames_per_second(self->framebuffer);
@@ -209,11 +218,13 @@ STATIC bool _refresh_area(framebufferio_framebufferdisplay_obj_t* self, const di
 
         uint8_t *buf = (uint8_t *)self->bufinfo.buf, *endbuf = buf + self->bufinfo.len;
         (void)endbuf; // Hint to compiler that endbuf is "used" even if NDEBUG
+        buf += self->first_pixel_offset;
 
-        uint8_t *dest = self->bufinfo.buf + (subrectangle.y1 * self->core.width + subrectangle.x1) * self->core.colorspace.depth / 8;
+        size_t rowstride = self->row_stride;
+        uint8_t *dest = buf + subrectangle.y1 * rowstride + subrectangle.x1 * self->core.colorspace.depth / 8;
         uint8_t *src = (uint8_t*)buffer;
         size_t rowsize = (subrectangle.x2 - subrectangle.x1) * self->core.colorspace.depth / 8;
-        size_t rowstride = self->core.width * self->core.colorspace.depth/8;
+
         for (uint16_t i = subrectangle.y1; i < subrectangle.y2; i++) {
             assert(dest >= buf && dest < endbuf && dest+rowsize <= endbuf);
             memcpy(dest, src, rowsize);
@@ -230,9 +241,9 @@ STATIC bool _refresh_area(framebufferio_framebufferdisplay_obj_t* self, const di
 
 STATIC void _refresh_display(framebufferio_framebufferdisplay_obj_t* self) {
     displayio_display_core_start_refresh(&self->core);
-    self->framebuffer_protocol->get_bufinfo(self->framebuffer, &self->bufinfo);
     const displayio_area_t* current_area = _get_refresh_areas(self);
     if (current_area) {
+        self->framebuffer_protocol->get_bufinfo(self->framebuffer, &self->bufinfo);
         while (current_area != NULL) {
             _refresh_area(self, current_area);
             current_area = current_area->next;
diff --git a/shared-module/framebufferio/FramebufferDisplay.h b/shared-module/framebufferio/FramebufferDisplay.h
index ca1ab984a3..1d207039ac 100644
--- a/shared-module/framebufferio/FramebufferDisplay.h
+++ b/shared-module/framebufferio/FramebufferDisplay.h
@@ -48,6 +48,7 @@ typedef struct {
     uint64_t last_refresh_call;
     uint16_t native_frames_per_second;
     uint16_t native_ms_per_frame;
+    uint16_t first_pixel_offset, row_stride;
     bool auto_refresh;
     bool first_manual_refresh;
 } framebufferio_framebufferdisplay_obj_t;
@@ -70,6 +71,8 @@ typedef bool (*framebuffer_set_auto_brightness_fun)(mp_obj_t, bool);
 typedef bool (*framebuffer_get_auto_brightness_fun)(mp_obj_t);
 typedef int (*framebuffer_get_width_fun)(mp_obj_t);
 typedef int (*framebuffer_get_height_fun)(mp_obj_t);
+typedef int (*framebuffer_get_row_stride_fun)(mp_obj_t);
+typedef int (*framebuffer_get_first_pixel_offset_fun)(mp_obj_t);
 typedef int (*framebuffer_get_color_depth_fun)(mp_obj_t);
 typedef int (*framebuffer_get_bytes_per_cell_fun)(mp_obj_t);
 typedef int (*framebuffer_get_native_frames_per_second_fun)(mp_obj_t);
@@ -86,6 +89,8 @@ typedef struct _framebuffer_p_t {
     framebuffer_get_native_frames_per_second_fun get_native_frames_per_second;
     framebuffer_get_brightness_fun get_brightness;
     framebuffer_set_brightness_fun set_brightness;
+    framebuffer_get_row_stride_fun get_row_stride;
+    framebuffer_get_first_pixel_offset_fun get_first_pixel_offset;
     framebuffer_get_auto_brightness_fun get_auto_brightness;
     framebuffer_set_auto_brightness_fun set_auto_brightness;
 } framebuffer_p_t;

From 1ee2062c1b64ecfda0af49cb0f721573aad7dea4 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Thu, 6 Aug 2020 14:28:22 -0500
Subject: [PATCH 09/19] framebufferio: Check early if framebuffer is big enough

---
 shared-module/framebufferio/FramebufferDisplay.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/shared-module/framebufferio/FramebufferDisplay.c b/shared-module/framebufferio/FramebufferDisplay.c
index e16777b83b..230dd6991d 100644
--- a/shared-module/framebufferio/FramebufferDisplay.c
+++ b/shared-module/framebufferio/FramebufferDisplay.c
@@ -79,6 +79,13 @@ void common_hal_framebufferio_framebufferdisplay_construct(framebufferio_framebu
     if (self->row_stride == 0) {
         self->row_stride = self->core.width * self->core.colorspace.depth/8;
     }
+
+    self->framebuffer_protocol->get_bufinfo(self->framebuffer, &self->bufinfo);
+    size_t framebuffer_size = self->first_pixel_offset + self->row_stride * self->core.height;
+    if (self->bufinfo.len < framebuffer_size) {
+        mp_raise_IndexError_varg(translate("Framebuffer requires %d bytes"), framebuffer_size);
+    }
+
     self->first_manual_refresh = !auto_refresh;
 
     self->native_frames_per_second = self->framebuffer_protocol->get_native_frames_per_second(self->framebuffer);

From 5e4ed9341586c3444409feeb61237e86a5c74c6f Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Thu, 6 Aug 2020 14:46:54 -0500
Subject: [PATCH 10/19] framebufferio: Add getters for remaining
 displayio_display_core_construct arguments

.. and introduce a convenience macro that helps many of them be required
(if their values match defaults or are inapplicable)
---
 .../framebufferio/FramebufferDisplay.c        | 27 +++++-----
 .../framebufferio/FramebufferDisplay.h        | 50 ++++++++++++-------
 2 files changed, 47 insertions(+), 30 deletions(-)

diff --git a/shared-module/framebufferio/FramebufferDisplay.c b/shared-module/framebufferio/FramebufferDisplay.c
index 230dd6991d..37989c29f7 100644
--- a/shared-module/framebufferio/FramebufferDisplay.c
+++ b/shared-module/framebufferio/FramebufferDisplay.c
@@ -40,6 +40,11 @@
 #include <stdint.h>
 #include <string.h>
 
+#define fb_getter_default(method, default_value) \
+    (self->framebuffer_protocol->method \
+        ? self->framebuffer_protocol->method(self->framebuffer) \
+        : (default_value))
+
 void common_hal_framebufferio_framebufferdisplay_construct(framebufferio_framebufferdisplay_obj_t* self,
         mp_obj_t framebuffer,
         uint16_t rotation,
@@ -51,7 +56,7 @@ void common_hal_framebufferio_framebufferdisplay_construct(framebufferio_framebu
 
     uint16_t ram_width = 0x100;
     uint16_t ram_height = 0x100;
-    uint16_t depth = self->framebuffer_protocol->get_color_depth(self->framebuffer);
+    uint16_t depth = fb_getter_default(get_color_depth, 16);
     displayio_display_core_construct(
         &self->core,
         NULL,
@@ -63,19 +68,15 @@ void common_hal_framebufferio_framebufferdisplay_construct(framebufferio_framebu
         0,
         rotation,
         depth,
-        (depth < 12), // grayscale
-        true, // pixels_in_byte_share_row
-        self->framebuffer_protocol->get_bytes_per_cell(self->framebuffer),
-        true, // reverse_pixels_in_byte
-        false // reverse_bytes_in_word
+        fb_getter_default(get_grayscale, (depth < 8)),
+        fb_getter_default(get_pixels_in_byte_share_row, false),
+        fb_getter_default(get_bytes_per_cell, 2),
+        fb_getter_default(get_reverse_pixels_in_byte, false),
+        fb_getter_default(get_reverse_pixels_in_word, false)
     );
 
-    self->first_pixel_offset = self->framebuffer_protocol->get_first_pixel_offset
-        ? self->framebuffer_protocol->get_first_pixel_offset(self->framebuffer)
-        : 0;
-    self->row_stride = self->framebuffer_protocol->get_row_stride
-        ? self->framebuffer_protocol->get_row_stride(self->framebuffer)
-        : 0;
+    self->first_pixel_offset = fb_getter_default(get_first_pixel_offset, 0);
+    self->row_stride = fb_getter_default(get_row_stride, 0);
     if (self->row_stride == 0) {
         self->row_stride = self->core.width * self->core.colorspace.depth/8;
     }
@@ -88,7 +89,7 @@ void common_hal_framebufferio_framebufferdisplay_construct(framebufferio_framebu
 
     self->first_manual_refresh = !auto_refresh;
 
-    self->native_frames_per_second = self->framebuffer_protocol->get_native_frames_per_second(self->framebuffer);
+    self->native_frames_per_second = fb_getter_default(get_native_frames_per_second, 60);
     self->native_ms_per_frame = 1000 / self->native_frames_per_second;
 
     supervisor_start_terminal(self->core.width, self->core.height);
diff --git a/shared-module/framebufferio/FramebufferDisplay.h b/shared-module/framebufferio/FramebufferDisplay.h
index 1d207039ac..93ad0118af 100644
--- a/shared-module/framebufferio/FramebufferDisplay.h
+++ b/shared-module/framebufferio/FramebufferDisplay.h
@@ -62,35 +62,51 @@ void framebufferio_framebufferdisplay_collect_ptrs(framebufferio_framebufferdisp
 
 mp_obj_t common_hal_framebufferio_framebufferdisplay_get_framebuffer(framebufferio_framebufferdisplay_obj_t* self);
 
+typedef bool (*framebuffer_get_auto_brightness_fun)(mp_obj_t);
+typedef bool (*framebuffer_get_reverse_pixels_in_byte_fun)(mp_obj_t);
+typedef bool (*framebuffer_get_reverse_pixels_in_word_fun)(mp_obj_t);
+typedef bool (*framebuffer_set_auto_brightness_fun)(mp_obj_t, bool);
+typedef bool (*framebuffer_set_brightness_fun)(mp_obj_t, mp_float_t);
+typedef int (*framebuffer_get_bytes_per_cell_fun)(mp_obj_t);
+typedef int (*framebuffer_get_color_depth_fun)(mp_obj_t);
+typedef int (*framebuffer_get_first_pixel_offset_fun)(mp_obj_t);
+typedef int (*framebuffer_get_grayscale_fun)(mp_obj_t);
+typedef int (*framebuffer_get_height_fun)(mp_obj_t);
+typedef int (*framebuffer_get_native_frames_per_second_fun)(mp_obj_t);
+typedef int (*framebuffer_get_pixels_in_byte_share_row_fun)(mp_obj_t);
+typedef int (*framebuffer_get_row_stride_fun)(mp_obj_t);
+typedef int (*framebuffer_get_width_fun)(mp_obj_t);
+typedef mp_float_t (*framebuffer_get_brightness_fun)(mp_obj_t);
+typedef void (*framebuffer_deinit_fun)(mp_obj_t);
 typedef void (*framebuffer_get_bufinfo_fun)(mp_obj_t, mp_buffer_info_t *bufinfo);
 typedef void (*framebuffer_swapbuffers_fun)(mp_obj_t);
-typedef void (*framebuffer_deinit_fun)(mp_obj_t);
-typedef bool (*framebuffer_set_brightness_fun)(mp_obj_t, mp_float_t);
-typedef mp_float_t (*framebuffer_get_brightness_fun)(mp_obj_t);
-typedef bool (*framebuffer_set_auto_brightness_fun)(mp_obj_t, bool);
-typedef bool (*framebuffer_get_auto_brightness_fun)(mp_obj_t);
-typedef int (*framebuffer_get_width_fun)(mp_obj_t);
-typedef int (*framebuffer_get_height_fun)(mp_obj_t);
-typedef int (*framebuffer_get_row_stride_fun)(mp_obj_t);
-typedef int (*framebuffer_get_first_pixel_offset_fun)(mp_obj_t);
-typedef int (*framebuffer_get_color_depth_fun)(mp_obj_t);
-typedef int (*framebuffer_get_bytes_per_cell_fun)(mp_obj_t);
-typedef int (*framebuffer_get_native_frames_per_second_fun)(mp_obj_t);
 
 typedef struct _framebuffer_p_t {
     MP_PROTOCOL_HEAD // MP_QSTR_protocol_framebuffer
+
+    // Mandatory
     framebuffer_get_bufinfo_fun get_bufinfo;
     framebuffer_swapbuffers_fun swapbuffers;
     framebuffer_deinit_fun deinit;
     framebuffer_get_width_fun get_width;
     framebuffer_get_height_fun get_height;
-    framebuffer_get_color_depth_fun get_color_depth;
-    framebuffer_get_bytes_per_cell_fun get_bytes_per_cell;
-    framebuffer_get_native_frames_per_second_fun get_native_frames_per_second;
+
+    // Optional getters
+    framebuffer_get_bytes_per_cell_fun get_bytes_per_cell; // default: 2
+    framebuffer_get_color_depth_fun get_color_depth; // default: 16
+    framebuffer_get_first_pixel_offset_fun get_first_pixel_offset; // default: 0
+    framebuffer_get_grayscale_fun get_grayscale; // default: grayscale if depth < 8
+    framebuffer_get_native_frames_per_second_fun get_native_frames_per_second; // default: 60
+    framebuffer_get_pixels_in_byte_share_row_fun get_pixels_in_byte_share_row; // default: false
+    framebuffer_get_reverse_pixels_in_byte_fun get_reverse_pixels_in_byte; // default: false
+    framebuffer_get_reverse_pixels_in_word_fun get_reverse_pixels_in_word; // default: false
+    framebuffer_get_row_stride_fun get_row_stride; // default: 0 (no extra row padding)
+
+    // Optional -- default is no brightness control
     framebuffer_get_brightness_fun get_brightness;
     framebuffer_set_brightness_fun set_brightness;
-    framebuffer_get_row_stride_fun get_row_stride;
-    framebuffer_get_first_pixel_offset_fun get_first_pixel_offset;
+
+    // Optional -- default is no automatic brightness control
     framebuffer_get_auto_brightness_fun get_auto_brightness;
     framebuffer_set_auto_brightness_fun set_auto_brightness;
 } framebuffer_p_t;

From 9c4f644641400c7b7eea37ace73782bc1cec2691 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Thu, 6 Aug 2020 14:51:52 -0500
Subject: [PATCH 11/19] framebufferio: add dirty row tracking

---
 shared-bindings/rgbmatrix/RGBMatrix.c            |  3 ++-
 shared-module/framebufferio/FramebufferDisplay.c | 10 +++++++---
 shared-module/framebufferio/FramebufferDisplay.h |  2 +-
 3 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/shared-bindings/rgbmatrix/RGBMatrix.c b/shared-bindings/rgbmatrix/RGBMatrix.c
index d6b79f5ebb..9cfc0d4095 100644
--- a/shared-bindings/rgbmatrix/RGBMatrix.c
+++ b/shared-bindings/rgbmatrix/RGBMatrix.c
@@ -352,7 +352,8 @@ STATIC void rgbmatrix_rgbmatrix_get_bufinfo(mp_obj_t self_in, mp_buffer_info_t *
 
 // These version exists so that the prototype matches the protocol,
 // avoiding a type cast that can hide errors
-STATIC void rgbmatrix_rgbmatrix_swapbuffers(mp_obj_t self_in) {
+STATIC void rgbmatrix_rgbmatrix_swapbuffers(mp_obj_t self_in, uint8_t *dirty_row_bitmap) {
+    (void)dirty_row_bitmap;
     common_hal_rgbmatrix_rgbmatrix_refresh(self_in);
 }
 
diff --git a/shared-module/framebufferio/FramebufferDisplay.c b/shared-module/framebufferio/FramebufferDisplay.c
index 37989c29f7..9a6797cd8c 100644
--- a/shared-module/framebufferio/FramebufferDisplay.c
+++ b/shared-module/framebufferio/FramebufferDisplay.c
@@ -156,7 +156,8 @@ STATIC const displayio_area_t* _get_refresh_areas(framebufferio_framebufferdispl
     return NULL;
 }
 
-STATIC bool _refresh_area(framebufferio_framebufferdisplay_obj_t* self, const displayio_area_t* area) {
+#define MARK_ROW_DIRTY(r) (dirty_row_bitmask[r/8] = (1 << (r & 7)))
+STATIC bool _refresh_area(framebufferio_framebufferdisplay_obj_t* self, const displayio_area_t* area, uint8_t *dirty_row_bitmask) {
     uint16_t buffer_size = 128; // In uint32_ts
 
     displayio_area_t clipped;
@@ -235,6 +236,7 @@ STATIC bool _refresh_area(framebufferio_framebufferdisplay_obj_t* self, const di
 
         for (uint16_t i = subrectangle.y1; i < subrectangle.y2; i++) {
             assert(dest >= buf && dest < endbuf && dest+rowsize <= endbuf);
+            MARK_ROW_DIRTY(i);
             memcpy(dest, src, rowsize);
             dest += rowstride;
             src += rowsize;
@@ -251,12 +253,14 @@ STATIC void _refresh_display(framebufferio_framebufferdisplay_obj_t* self) {
     displayio_display_core_start_refresh(&self->core);
     const displayio_area_t* current_area = _get_refresh_areas(self);
     if (current_area) {
+        uint8_t dirty_row_bitmask[(self->core.height + 7) / 8];
+        memset(dirty_row_bitmask, 0, sizeof(dirty_row_bitmask));
         self->framebuffer_protocol->get_bufinfo(self->framebuffer, &self->bufinfo);
         while (current_area != NULL) {
-            _refresh_area(self, current_area);
+            _refresh_area(self, current_area, dirty_row_bitmask);
             current_area = current_area->next;
         }
-        self->framebuffer_protocol->swapbuffers(self->framebuffer);
+        self->framebuffer_protocol->swapbuffers(self->framebuffer, dirty_row_bitmask);
     }
     displayio_display_core_finish_refresh(&self->core);
 }
diff --git a/shared-module/framebufferio/FramebufferDisplay.h b/shared-module/framebufferio/FramebufferDisplay.h
index 93ad0118af..027086b5a1 100644
--- a/shared-module/framebufferio/FramebufferDisplay.h
+++ b/shared-module/framebufferio/FramebufferDisplay.h
@@ -79,7 +79,7 @@ typedef int (*framebuffer_get_width_fun)(mp_obj_t);
 typedef mp_float_t (*framebuffer_get_brightness_fun)(mp_obj_t);
 typedef void (*framebuffer_deinit_fun)(mp_obj_t);
 typedef void (*framebuffer_get_bufinfo_fun)(mp_obj_t, mp_buffer_info_t *bufinfo);
-typedef void (*framebuffer_swapbuffers_fun)(mp_obj_t);
+typedef void (*framebuffer_swapbuffers_fun)(mp_obj_t, uint8_t *dirty_row_bitmask);
 
 typedef struct _framebuffer_p_t {
     MP_PROTOCOL_HEAD // MP_QSTR_protocol_framebuffer

From c1400bae9bbdd55f650ddfe24edf6778f08c35b8 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Thu, 6 Aug 2020 16:03:31 -0500
Subject: [PATCH 12/19] sharpmemory: Implement support for Sharp Memory
 Displays in framebufferio

---
 py/circuitpy_defns.mk                         |   5 +
 py/circuitpy_mpconfig.h                       |  22 +-
 py/circuitpy_mpconfig.mk                      |   6 +-
 py/qstr.c                                     |   1 +
 .../sharpdisplay/SharpMemoryFramebuffer.c     |  92 ++++++
 .../sharpdisplay/SharpMemoryFramebuffer.h     |  34 +++
 shared-bindings/sharpdisplay/__init__.c       |  47 +++
 shared-bindings/sharpdisplay/__init__.h       |   0
 shared-module/displayio/__init__.c            |  33 +-
 shared-module/displayio/__init__.h            |  10 +
 .../framebufferio/FramebufferDisplay.c        |  21 +-
 .../framebufferio/FramebufferDisplay.h        |   3 +-
 .../sharpdisplay/SharpMemoryFramebuffer.c     | 282 ++++++++++++++++++
 .../sharpdisplay/SharpMemoryFramebuffer.h     |  60 ++++
 shared-module/sharpdisplay/__init__.c         |   0
 shared-module/sharpdisplay/__init__.h         |   0
 supervisor/shared/display.c                   |  21 +-
 17 files changed, 608 insertions(+), 29 deletions(-)
 create mode 100644 shared-bindings/sharpdisplay/SharpMemoryFramebuffer.c
 create mode 100644 shared-bindings/sharpdisplay/SharpMemoryFramebuffer.h
 create mode 100644 shared-bindings/sharpdisplay/__init__.c
 create mode 100644 shared-bindings/sharpdisplay/__init__.h
 create mode 100644 shared-module/sharpdisplay/SharpMemoryFramebuffer.c
 create mode 100644 shared-module/sharpdisplay/SharpMemoryFramebuffer.h
 create mode 100644 shared-module/sharpdisplay/__init__.c
 create mode 100644 shared-module/sharpdisplay/__init__.h

diff --git a/py/circuitpy_defns.mk b/py/circuitpy_defns.mk
index a39e0c9ddf..515b386f9e 100644
--- a/py/circuitpy_defns.mk
+++ b/py/circuitpy_defns.mk
@@ -222,6 +222,9 @@ endif
 ifeq ($(CIRCUITPY_SDIOIO),1)
 SRC_PATTERNS += sdioio/%
 endif
+ifeq ($(CIRCUITPY_SHARPDISPLAY),1)
+SRC_PATTERNS += sharpdisplay/%
+endif
 ifeq ($(CIRCUITPY_STAGE),1)
 SRC_PATTERNS += _stage/%
 endif
@@ -409,6 +412,8 @@ SRC_SHARED_MODULE_ALL = \
 	random/__init__.c \
 	rgbmatrix/RGBMatrix.c \
 	rgbmatrix/__init__.c \
+	sharpdisplay/SharpMemoryFramebuffer.c \
+	sharpdisplay/__init__.c \
 	socket/__init__.c \
 	storage/__init__.c \
 	struct/__init__.c \
diff --git a/py/circuitpy_mpconfig.h b/py/circuitpy_mpconfig.h
index 255ab99b93..f0e8adffa1 100644
--- a/py/circuitpy_mpconfig.h
+++ b/py/circuitpy_mpconfig.h
@@ -499,13 +499,6 @@ extern const struct _mp_obj_module_t pixelbuf_module;
 #define PIXELBUF_MODULE
 #endif
 
-#if CIRCUITPY_RGBMATRIX
-extern const struct _mp_obj_module_t rgbmatrix_module;
-#define RGBMATRIX_MODULE        { MP_OBJ_NEW_QSTR(MP_QSTR_rgbmatrix),(mp_obj_t)&rgbmatrix_module },
-#else
-#define RGBMATRIX_MODULE
-#endif
-
 #if CIRCUITPY_PULSEIO
 extern const struct _mp_obj_module_t pulseio_module;
 #define PULSEIO_MODULE         { MP_OBJ_NEW_QSTR(MP_QSTR_pulseio), (mp_obj_t)&pulseio_module },
@@ -520,6 +513,13 @@ extern const struct _mp_obj_module_t ps2io_module;
 #define PS2IO_MODULE
 #endif
 
+#if CIRCUITPY_RGBMATRIX
+extern const struct _mp_obj_module_t rgbmatrix_module;
+#define RGBMATRIX_MODULE        { MP_OBJ_NEW_QSTR(MP_QSTR_rgbmatrix),(mp_obj_t)&rgbmatrix_module },
+#else
+#define RGBMATRIX_MODULE
+#endif
+
 #if CIRCUITPY_RANDOM
 extern const struct _mp_obj_module_t random_module;
 #define RANDOM_MODULE          { MP_OBJ_NEW_QSTR(MP_QSTR_random), (mp_obj_t)&random_module },
@@ -562,6 +562,13 @@ extern const struct _mp_obj_module_t sdioio_module;
 #define SDIOIO_MODULE
 #endif
 
+#if CIRCUITPY_SHARPDISPLAY
+extern const struct _mp_obj_module_t sharpdisplay_module;
+#define SHARPDISPLAY_MODULE        { MP_OBJ_NEW_QSTR(MP_QSTR_sharpdisplay),(mp_obj_t)&sharpdisplay_module },
+#else
+#define SHARPDISPLAY_MODULE
+#endif
+
 #if CIRCUITPY_STAGE
 extern const struct _mp_obj_module_t stage_module;
 #define STAGE_MODULE           { MP_OBJ_NEW_QSTR(MP_QSTR__stage), (mp_obj_t)&stage_module },
@@ -737,6 +744,7 @@ extern const struct _mp_obj_module_t watchdog_module;
     SAMD_MODULE \
     SDCARDIO_MODULE \
     SDIOIO_MODULE \
+    SHARPDISPLAY_MODULE \
     STAGE_MODULE \
     STORAGE_MODULE \
     STRUCT_MODULE \
diff --git a/py/circuitpy_mpconfig.mk b/py/circuitpy_mpconfig.mk
index 2cf8426e5f..1ba71fa023 100644
--- a/py/circuitpy_mpconfig.mk
+++ b/py/circuitpy_mpconfig.mk
@@ -95,7 +95,7 @@ CFLAGS += -DCIRCUITPY_COUNTIO=$(CIRCUITPY_COUNTIO)
 CIRCUITPY_DISPLAYIO ?= $(CIRCUITPY_FULL_BUILD)
 CFLAGS += -DCIRCUITPY_DISPLAYIO=$(CIRCUITPY_DISPLAYIO)
 
-CIRCUITPY_FRAMEBUFFERIO ?= 0
+CIRCUITPY_FRAMEBUFFERIO ?= $(CIRCUITPY_FULL_BUILD)
 CFLAGS += -DCIRCUITPY_FRAMEBUFFERIO=$(CIRCUITPY_FRAMEBUFFERIO)
 
 CIRCUITPY_VECTORIO ?= $(CIRCUITPY_DISPLAYIO)
@@ -144,7 +144,6 @@ CFLAGS += -DCIRCUITPY_OS=$(CIRCUITPY_OS)
 CIRCUITPY_PIXELBUF ?= $(CIRCUITPY_FULL_BUILD)
 CFLAGS += -DCIRCUITPY_PIXELBUF=$(CIRCUITPY_PIXELBUF)
 
-# Only for SAMD boards for the moment
 CIRCUITPY_RGBMATRIX ?= 0
 CFLAGS += -DCIRCUITPY_RGBMATRIX=$(CIRCUITPY_RGBMATRIX)
 
@@ -176,6 +175,9 @@ CFLAGS += -DCIRCUITPY_SDCARDIO=$(CIRCUITPY_SDCARDIO)
 CIRCUITPY_SDIOIO ?= 0
 CFLAGS += -DCIRCUITPY_SDIOIO=$(CIRCUITPY_SDIOIO)
 
+CIRCUITPY_SHARPDISPLAY ?= $(CIRCUITPY_FRAMEBUFFERIO)
+CFLAGS += -DCIRCUITPY_SHARPDISPLAY=$(CIRCUITPY_SHARPDISPLAY)
+
 # Currently always off.
 CIRCUITPY_STAGE ?= 0
 CFLAGS += -DCIRCUITPY_STAGE=$(CIRCUITPY_STAGE)
diff --git a/py/qstr.c b/py/qstr.c
index 17d8517c93..c9ba298fb7 100755
--- a/py/qstr.c
+++ b/py/qstr.c
@@ -137,6 +137,7 @@ STATIC const byte *find_qstr(qstr q) {
     while (q < pool->total_prev_len) {
         pool = pool->prev;
     }
+    assert(q - pool->total_prev_len < pool->len);
     return pool->qstrs[q - pool->total_prev_len];
 }
 
diff --git a/shared-bindings/sharpdisplay/SharpMemoryFramebuffer.c b/shared-bindings/sharpdisplay/SharpMemoryFramebuffer.c
new file mode 100644
index 0000000000..e8f4e970a2
--- /dev/null
+++ b/shared-bindings/sharpdisplay/SharpMemoryFramebuffer.c
@@ -0,0 +1,92 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/objarray.h"
+#include "py/runtime.h"
+
+#include "shared-bindings/busio/SPI.h"
+#include "shared-bindings/microcontroller/Pin.h"
+#include "shared-bindings/sharpdisplay/SharpMemoryFramebuffer.h"
+#include "shared-module/displayio/__init__.h"
+#include "shared-module/sharpdisplay/SharpMemoryFramebuffer.h"
+
+STATIC mp_obj_t sharpdisplay_framebuffer_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_spi_bus, ARG_chip_select, ARG_width, ARG_height, ARG_baudrate, NUM_ARGS };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_spi_bus, MP_ARG_OBJ | MP_ARG_REQUIRED, {.u_obj = MP_OBJ_NULL} },
+        { MP_QSTR_chip_select, MP_ARG_OBJ | MP_ARG_REQUIRED, {.u_obj = MP_OBJ_NULL} },
+        { MP_QSTR_width, MP_ARG_INT | MP_ARG_REQUIRED, {.u_int = 0} },
+        { MP_QSTR_height, MP_ARG_INT | MP_ARG_REQUIRED, {.u_int = 0} },
+        { MP_QSTR_baudrate, MP_ARG_INT, {.u_int = 2000000} },
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    MP_STATIC_ASSERT( MP_ARRAY_SIZE(allowed_args) == NUM_ARGS );
+
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    mcu_pin_obj_t *chip_select = validate_obj_is_free_pin(args[ARG_chip_select].u_obj);
+    busio_spi_obj_t *spi = validate_obj_is_spi_bus(args[ARG_spi_bus].u_obj);
+
+    sharpdisplay_framebuffer_obj_t* self = &allocate_display_bus_or_raise()->sharpdisplay;
+    self->base.type = &sharpdisplay_framebuffer_type;
+
+    common_hal_sharpdisplay_framebuffer_construct(self, spi, chip_select, args[ARG_baudrate].u_int, args[ARG_width].u_int, args[ARG_height].u_int);
+
+    return MP_OBJ_FROM_PTR(self);
+}
+
+
+STATIC mp_int_t sharpdisplay_framebuffer_get_buffer(mp_obj_t self_in, mp_buffer_info_t *bufinfo, mp_uint_t flags) {
+    sharpdisplay_framebuffer_obj_t *self = (sharpdisplay_framebuffer_obj_t*)self_in;
+    // a readonly framebuffer would be unusual but not impossible
+    if ((flags & MP_BUFFER_WRITE) && !(self->bufinfo.typecode & MP_OBJ_ARRAY_TYPECODE_FLAG_RW)) {
+        return 1;
+    }
+    *bufinfo = self->bufinfo;
+    return 0;
+}
+
+STATIC mp_obj_t sharpdisplay_framebuffer_deinit(mp_obj_t self_in) {
+    sharpdisplay_framebuffer_obj_t *self = (sharpdisplay_framebuffer_obj_t*)self_in;
+    common_hal_sharpdisplay_framebuffer_deinit(self);
+
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(sharpdisplay_framebuffer_deinit_obj, sharpdisplay_framebuffer_deinit);
+
+STATIC const mp_rom_map_elem_t sharpdisplay_framebuffer_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&sharpdisplay_framebuffer_deinit_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(sharpdisplay_framebuffer_locals_dict, sharpdisplay_framebuffer_locals_dict_table);
+
+const mp_obj_type_t sharpdisplay_framebuffer_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_SharpMemoryFramebuffer,
+    .buffer_p = { .get_buffer = sharpdisplay_framebuffer_get_buffer, },
+    .make_new = sharpdisplay_framebuffer_make_new,
+    .protocol = &sharpdisplay_framebuffer_proto,
+    .locals_dict = (mp_obj_dict_t*)&sharpdisplay_framebuffer_locals_dict,
+};
diff --git a/shared-bindings/sharpdisplay/SharpMemoryFramebuffer.h b/shared-bindings/sharpdisplay/SharpMemoryFramebuffer.h
new file mode 100644
index 0000000000..30f1b867b1
--- /dev/null
+++ b/shared-bindings/sharpdisplay/SharpMemoryFramebuffer.h
@@ -0,0 +1,34 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+// #include "shared-module/sharpdisplay/SharpMemoryFramebuffer.h"
+// #include "shared-module/framebufferio/FramebufferDisplay.h"
+
+#include "py/objtype.h"
+
+extern const mp_obj_type_t sharpdisplay_framebuffer_type;
diff --git a/shared-bindings/sharpdisplay/__init__.c b/shared-bindings/sharpdisplay/__init__.c
new file mode 100644
index 0000000000..d1f728c61b
--- /dev/null
+++ b/shared-bindings/sharpdisplay/__init__.c
@@ -0,0 +1,47 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdint.h>
+
+#include "py/obj.h"
+#include "py/runtime.h"
+
+#include "shared-bindings/sharpdisplay/SharpMemoryFramebuffer.h"
+
+//| """Support for Sharp Memory Display framebuffers"""
+//|
+
+STATIC const mp_rom_map_elem_t sharpdisplay_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_sharpdisplay) },
+    { MP_ROM_QSTR(MP_QSTR_SharpMemoryFramebuffer), MP_ROM_PTR(&sharpdisplay_framebuffer_type) },
+};
+
+STATIC MP_DEFINE_CONST_DICT(sharpdisplay_module_globals, sharpdisplay_module_globals_table);
+
+const mp_obj_module_t sharpdisplay_module = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t*)&sharpdisplay_module_globals,
+};
diff --git a/shared-bindings/sharpdisplay/__init__.h b/shared-bindings/sharpdisplay/__init__.h
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/shared-module/displayio/__init__.c b/shared-module/displayio/__init__.c
index efc28470fb..e52ec5b9e3 100644
--- a/shared-module/displayio/__init__.c
+++ b/shared-module/displayio/__init__.c
@@ -19,14 +19,19 @@
 #include "supervisor/spi_flash_api.h"
 #include "py/mpconfig.h"
 
+#if CIRCUITPY_SHARPDISPLAY
+#include "shared-bindings/sharpdisplay/SharpMemoryFramebuffer.h"
+#include "shared-module/sharpdisplay/SharpMemoryFramebuffer.h"
+#endif
+
 primary_display_t displays[CIRCUITPY_DISPLAY_LIMIT];
 
-#if CIRCUITPY_RGBMATRIX
-STATIC bool any_display_uses_this_rgbmatrix(rgbmatrix_rgbmatrix_obj_t* pm) {
+#if CIRCUITPY_RGBMATRIX || CIRCUITPY_SHARPDISPLAY
+STATIC bool any_display_uses_this_framebuffer(mp_obj_base_t *obj) {
     for (uint8_t i = 0; i < CIRCUITPY_DISPLAY_LIMIT; i++) {
-        if (displays[i].framebuffer_display.base.type == &framebufferio_framebufferdisplay_type) {
+        if (displays[i].display_base.type == &framebufferio_framebufferdisplay_type) {
             framebufferio_framebufferdisplay_obj_t* display = &displays[i].framebuffer_display;
-            if (display->framebuffer == pm) {
+            if (display->framebuffer == obj) {
                 return true;
             }
         }
@@ -105,6 +110,10 @@ void common_hal_displayio_release_displays(void) {
 #if CIRCUITPY_FRAMEBUFFERIO
         } else if (bus_type == &rgbmatrix_RGBMatrix_type) {
             common_hal_rgbmatrix_rgbmatrix_deinit(&displays[i].rgbmatrix);
+#endif
+#if CIRCUITPY_SHARPDISPLAY
+        } else if (displays[i].bus_base.type == &sharpdisplay_framebuffer_type) {
+            common_hal_sharpdisplay_framebuffer_deinit(&displays[i].sharpdisplay);
 #endif
         }
         displays[i].fourwire_bus.base.type = &mp_type_NoneType;
@@ -170,9 +179,18 @@ void reset_displays(void) {
 #if CIRCUITPY_RGBMATRIX
         } else if (displays[i].rgbmatrix.base.type == &rgbmatrix_RGBMatrix_type) {
             rgbmatrix_rgbmatrix_obj_t * pm = &displays[i].rgbmatrix;
-            if(!any_display_uses_this_rgbmatrix(pm)) {
+            if(!any_display_uses_this_framebuffer(&pm->base)) {
                 common_hal_rgbmatrix_rgbmatrix_deinit(pm);
             }
+#endif
+#if CIRCUITPY_SHARPDISPLAY
+        } else if (displays[i].bus_base.type == &sharpdisplay_framebuffer_type) {
+            sharpdisplay_framebuffer_obj_t * sharp = &displays[i].sharpdisplay;
+            if(any_display_uses_this_framebuffer(&sharp->base)) {
+                common_hal_sharpdisplay_framebuffer_reset(sharp);
+            } else {
+                common_hal_sharpdisplay_framebuffer_deinit(sharp);
+            }
 #endif
         } else {
             // Not an active display bus.
@@ -203,6 +221,11 @@ void displayio_gc_collect(void) {
             rgbmatrix_rgbmatrix_collect_ptrs(&displays[i].rgbmatrix);
         }
 #endif
+#if CIRCUITPY_SHARPDISPLAY
+        if (displays[i].rgbmatrix.base.type == &sharpdisplay_framebuffer_type) {
+            common_hal_sharpdisplay_framebuffer_collect_ptrs(&displays[i].sharpdisplay);
+        }
+#endif
 
         if (displays[i].display.base.type == NULL) {
             continue;
diff --git a/shared-module/displayio/__init__.h b/shared-module/displayio/__init__.h
index 9eb10c28b2..44ad5a9a98 100644
--- a/shared-module/displayio/__init__.h
+++ b/shared-module/displayio/__init__.h
@@ -36,18 +36,28 @@
 #include "shared-bindings/displayio/Group.h"
 #include "shared-bindings/displayio/I2CDisplay.h"
 #include "shared-bindings/displayio/ParallelBus.h"
+#if CIRCUITPY_RGBMATRIX
 #include "shared-bindings/rgbmatrix/RGBMatrix.h"
+#endif
+#if CIRCUITPY_SHARPDISPLAY
+#include "shared-module/sharpdisplay/SharpMemoryFramebuffer.h"
+#endif
 
 typedef struct {
     union {
+        mp_obj_base_t bus_base;
         displayio_fourwire_obj_t fourwire_bus;
         displayio_i2cdisplay_obj_t i2cdisplay_bus;
         displayio_parallelbus_obj_t parallel_bus;
 #if CIRCUITPY_RGBMATRIX
         rgbmatrix_rgbmatrix_obj_t rgbmatrix;
+#endif
+#if CIRCUITPY_SHARPDISPLAY
+        sharpdisplay_framebuffer_obj_t sharpdisplay;
 #endif
     };
     union {
+        mp_obj_base_t display_base;
         displayio_display_obj_t display;
         displayio_epaperdisplay_obj_t epaper_display;
 #if CIRCUITPY_FRAMEBUFFERIO
diff --git a/shared-module/framebufferio/FramebufferDisplay.c b/shared-module/framebufferio/FramebufferDisplay.c
index 9a6797cd8c..6b5346877c 100644
--- a/shared-module/framebufferio/FramebufferDisplay.c
+++ b/shared-module/framebufferio/FramebufferDisplay.c
@@ -156,7 +156,7 @@ STATIC const displayio_area_t* _get_refresh_areas(framebufferio_framebufferdispl
     return NULL;
 }
 
-#define MARK_ROW_DIRTY(r) (dirty_row_bitmask[r/8] = (1 << (r & 7)))
+#define MARK_ROW_DIRTY(r) (dirty_row_bitmask[r/8] |= (1 << (r & 7)))
 STATIC bool _refresh_area(framebufferio_framebufferdisplay_obj_t* self, const displayio_area_t* area, uint8_t *dirty_row_bitmask) {
     uint16_t buffer_size = 128; // In uint32_ts
 
@@ -250,6 +250,10 @@ STATIC bool _refresh_area(framebufferio_framebufferdisplay_obj_t* self, const di
 }
 
 STATIC void _refresh_display(framebufferio_framebufferdisplay_obj_t* self) {
+    self->framebuffer_protocol->get_bufinfo(self->framebuffer, &self->bufinfo);
+    if(!self->bufinfo.buf) {
+        return;
+    }
     displayio_display_core_start_refresh(&self->core);
     const displayio_area_t* current_area = _get_refresh_areas(self);
     if (current_area) {
@@ -348,17 +352,18 @@ void release_framebufferdisplay(framebufferio_framebufferdisplay_obj_t* self) {
     self->base.type = &mp_type_NoneType;
 }
 
-void reset_framebufferdisplay(framebufferio_framebufferdisplay_obj_t* self) {
-    common_hal_framebufferio_framebufferdisplay_set_auto_refresh(self, true);
-    common_hal_framebufferio_framebufferdisplay_show(self, NULL);
-}
-
 void framebufferio_framebufferdisplay_collect_ptrs(framebufferio_framebufferdisplay_obj_t* self) {
     gc_collect_ptr(self->framebuffer);
     displayio_display_core_collect_ptrs(&self->core);
 }
 
 void framebufferio_framebufferdisplay_reset(framebufferio_framebufferdisplay_obj_t* self) {
-    common_hal_framebufferio_framebufferdisplay_set_auto_refresh(self, true);
-    common_hal_framebufferio_framebufferdisplay_show(self, NULL);
+    mp_obj_type_t *fb_type = mp_obj_get_type(self->framebuffer);
+    if(fb_type != NULL && fb_type != &mp_type_NoneType) {
+        common_hal_framebufferio_framebufferdisplay_set_auto_refresh(self, true);
+        common_hal_framebufferio_framebufferdisplay_show(self, NULL);
+        self->core.full_refresh = true;
+    } else {
+        release_framebufferdisplay(self);
+    }
 }
diff --git a/shared-module/framebufferio/FramebufferDisplay.h b/shared-module/framebufferio/FramebufferDisplay.h
index 027086b5a1..111c9f670d 100644
--- a/shared-module/framebufferio/FramebufferDisplay.h
+++ b/shared-module/framebufferio/FramebufferDisplay.h
@@ -55,7 +55,6 @@ typedef struct {
 
 void framebufferio_framebufferdisplay_background(framebufferio_framebufferdisplay_obj_t* self);
 void release_framebufferdisplay(framebufferio_framebufferdisplay_obj_t* self);
-void reset_framebufferdisplay(framebufferio_framebufferdisplay_obj_t* self);
 void framebufferio_framebufferdisplay_reset(framebufferio_framebufferdisplay_obj_t* self);
 
 void framebufferio_framebufferdisplay_collect_ptrs(framebufferio_framebufferdisplay_obj_t* self);
@@ -73,7 +72,7 @@ typedef int (*framebuffer_get_first_pixel_offset_fun)(mp_obj_t);
 typedef int (*framebuffer_get_grayscale_fun)(mp_obj_t);
 typedef int (*framebuffer_get_height_fun)(mp_obj_t);
 typedef int (*framebuffer_get_native_frames_per_second_fun)(mp_obj_t);
-typedef int (*framebuffer_get_pixels_in_byte_share_row_fun)(mp_obj_t);
+typedef bool (*framebuffer_get_pixels_in_byte_share_row_fun)(mp_obj_t);
 typedef int (*framebuffer_get_row_stride_fun)(mp_obj_t);
 typedef int (*framebuffer_get_width_fun)(mp_obj_t);
 typedef mp_float_t (*framebuffer_get_brightness_fun)(mp_obj_t);
diff --git a/shared-module/sharpdisplay/SharpMemoryFramebuffer.c b/shared-module/sharpdisplay/SharpMemoryFramebuffer.c
new file mode 100644
index 0000000000..ac9c225729
--- /dev/null
+++ b/shared-module/sharpdisplay/SharpMemoryFramebuffer.c
@@ -0,0 +1,282 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <string.h>
+
+#include "py/gc.h"
+
+#include "shared-bindings/board/__init__.h"
+#include "shared-bindings/microcontroller/Pin.h"
+#include "shared-bindings/sharpdisplay/SharpMemoryFramebuffer.h"
+#include "shared-module/sharpdisplay/SharpMemoryFramebuffer.h"
+
+#include "supervisor/memory.h"
+
+#define SHARPMEM_BIT_WRITECMD_LSB (0x80)
+#define SHARPMEM_BIT_VCOM_LSB (0x40)
+
+static inline void *hybrid_alloc(size_t sz) {
+    if (gc_alloc_possible()) {
+        return m_malloc(sz + sizeof(void*), true);
+    } else {
+        supervisor_allocation *allocation = allocate_memory(align32_size(sz), false);
+        if (!allocation) {
+            return NULL;
+        }
+        memset(allocation->ptr, 0, sz);
+        return allocation->ptr;
+    }
+}
+
+static inline void hybrid_free(void *ptr_in) {
+    supervisor_allocation *allocation = allocation_from_ptr(ptr_in);
+
+    if (allocation) {
+        free_memory(allocation);
+    }
+}
+
+STATIC uint8_t bitrev(uint8_t n) {
+    uint8_t r = 0;
+    for(int i=0;i<8;i++) r |= ((n>>i) & 1)<<(7-i);
+    return r;
+}
+
+int common_hal_sharpdisplay_framebuffer_get_width(sharpdisplay_framebuffer_obj_t *self) {
+    return self->width;
+}
+
+int common_hal_sharpdisplay_framebuffer_get_height(sharpdisplay_framebuffer_obj_t *self) {
+    return self->height;
+}
+
+int common_hal_sharpdisplay_framebuffer_get_row_stride(sharpdisplay_framebuffer_obj_t *self) {
+    return (self->width + 7) / 8 + 2;
+}
+
+int common_hal_sharpdisplay_framebuffer_get_first_pixel_offset(sharpdisplay_framebuffer_obj_t *self) {
+    return 2;
+}
+
+bool common_hal_sharpdisplay_framebuffer_get_reverse_pixels_in_byte(sharpdisplay_framebuffer_obj_t *self) {
+    return true;
+}
+
+bool common_hal_sharpdisplay_framebuffer_get_pixels_in_byte_share_row(sharpdisplay_framebuffer_obj_t *self) {
+    return true;
+}
+
+void common_hal_sharpdisplay_framebuffer_reset(sharpdisplay_framebuffer_obj_t *self) {
+    if (!allocation_from_ptr(self->bufinfo.buf)) {
+        self->bufinfo.buf = NULL;
+    }
+
+    if (self->bus != &self->inline_bus
+#if BOARD_SPI
+        && self->bus != common_hal_board_get_spi()
+#endif
+    ) {
+        memcpy(&self->inline_bus, self->bus, sizeof(busio_spi_obj_t));
+        self->bus = &self->inline_bus;
+    }
+}
+
+void common_hal_sharpdisplay_framebuffer_reconstruct(sharpdisplay_framebuffer_obj_t *self) {
+
+}
+
+void common_hal_sharpdisplay_framebuffer_get_bufinfo(sharpdisplay_framebuffer_obj_t *self, mp_buffer_info_t *bufinfo) {
+    if (!self->bufinfo.buf) {
+        int row_stride = common_hal_sharpdisplay_framebuffer_get_row_stride(self);
+        int height = common_hal_sharpdisplay_framebuffer_get_height(self);
+        self->bufinfo.len = row_stride * height + 2;
+        self->bufinfo.buf = hybrid_alloc(self->bufinfo.len);
+
+        uint8_t *data = self->bufinfo.buf;
+        *data++ = SHARPMEM_BIT_WRITECMD_LSB;
+
+        for(int y=0; y<height; y++) {
+            *data = bitrev(y+1);
+            data += row_stride;
+        }
+        self->full_refresh = true;
+    }
+    *bufinfo = self->bufinfo;
+}
+
+void common_hal_sharpdisplay_framebuffer_deinit(sharpdisplay_framebuffer_obj_t *self) {
+    if (self->base.type != &sharpdisplay_framebuffer_type) {
+        return;
+    }
+
+    if (self->bus == &self->inline_bus) {
+        common_hal_busio_spi_deinit(self->bus);
+    }
+
+    common_hal_reset_pin(self->chip_select.pin);
+
+    hybrid_free(self->bufinfo.buf);
+
+    memset(self, 0, sizeof(*self));
+}
+
+void common_hal_sharpdisplay_framebuffer_construct(sharpdisplay_framebuffer_obj_t *self, busio_spi_obj_t *spi, mcu_pin_obj_t *chip_select, int baudrate, int width, int height) {
+    common_hal_digitalio_digitalinout_construct(&self->chip_select, chip_select);
+    common_hal_digitalio_digitalinout_switch_to_output(&self->chip_select, true, DRIVE_MODE_PUSH_PULL);
+    common_hal_never_reset_pin(chip_select);
+
+    self->bus = spi;
+    common_hal_busio_spi_never_reset(self->bus);
+
+    self->width = width;
+    self->height = height;
+    self->baudrate = baudrate;
+
+    int row_stride = common_hal_sharpdisplay_framebuffer_get_row_stride(self);
+    self->bufinfo.len = row_stride * height + 2;
+    self->bufinfo.buf = gc_alloc(self->bufinfo.len, false, true);
+
+    uint8_t *data = self->bufinfo.buf;
+    *data++ = SHARPMEM_BIT_WRITECMD_LSB;
+
+    for(int y=0; y<self->height; y++) {
+        *data = bitrev(y+1);
+        data += row_stride;
+    }
+    self->full_refresh = true;
+}
+
+void common_hal_sharpdisplay_framebuffer_swapbuffers(sharpdisplay_framebuffer_obj_t *self, uint8_t *dirty_row_bitmask) {
+    // claim SPI bus
+    if (!common_hal_busio_spi_try_lock(self->bus)) {
+        return;
+    }
+    common_hal_busio_spi_configure(self->bus, self->baudrate, 0, 0, 8);
+
+    // set chip select high
+    common_hal_digitalio_digitalinout_set_value(&self->chip_select, true);
+
+    // output the toggling signal
+    uint8_t *data = self->bufinfo.buf;
+    data[0] ^= SHARPMEM_BIT_VCOM_LSB;
+
+#define PARTIAL_UPDATES (1)
+#if PARTIAL_UPDATES
+    common_hal_busio_spi_write(self->bus, data++, 1);
+
+    // output each changed row
+    size_t row_stride = common_hal_sharpdisplay_framebuffer_get_row_stride(self);
+    for(int y=0; y<self->height; y++) {
+        if(self->full_refresh || (dirty_row_bitmask[y/8] & (1 << (y & 7)))) {
+            common_hal_busio_spi_write(self->bus, data, row_stride);
+        }
+        data += row_stride;
+    }
+
+    // output a trailing zero
+    common_hal_busio_spi_write(self->bus, data, 1);
+#else
+    common_hal_busio_spi_write(self->bus, data, self->bufinfo.len);
+#endif
+
+    // set chip select low
+    common_hal_digitalio_digitalinout_set_value(&self->chip_select, false);
+
+    // release SPI bus
+    common_hal_busio_spi_unlock(self->bus);
+
+    self->full_refresh = false;
+}
+
+STATIC void sharpdisplay_framebuffer_deinit(mp_obj_t self_in) {
+    sharpdisplay_framebuffer_obj_t *self = self_in;
+    common_hal_sharpdisplay_framebuffer_deinit(self);
+}
+
+STATIC void sharpdisplay_framebuffer_get_bufinfo(mp_obj_t self_in, mp_buffer_info_t *bufinfo) {
+    sharpdisplay_framebuffer_obj_t *self = self_in;
+    common_hal_sharpdisplay_framebuffer_get_bufinfo(self, bufinfo);
+}
+
+STATIC int sharpdisplay_framebuffer_get_color_depth(mp_obj_t self_in) {
+    return 1;
+}
+
+STATIC int sharpdisplay_framebuffer_get_height(mp_obj_t self_in) {
+    sharpdisplay_framebuffer_obj_t *self = self_in;
+    return common_hal_sharpdisplay_framebuffer_get_height(self);
+}
+
+STATIC int sharpdisplay_framebuffer_get_width(mp_obj_t self_in) {
+    sharpdisplay_framebuffer_obj_t *self = self_in;
+    return common_hal_sharpdisplay_framebuffer_get_width(self);
+}
+
+STATIC int sharpdisplay_framebuffer_get_first_pixel_offset(mp_obj_t self_in) {
+    sharpdisplay_framebuffer_obj_t *self = self_in;
+    return common_hal_sharpdisplay_framebuffer_get_first_pixel_offset(self);
+}
+
+STATIC bool sharpdisplay_framebuffer_get_pixels_in_byte_share_row(mp_obj_t self_in) {
+    sharpdisplay_framebuffer_obj_t *self = self_in;
+    return common_hal_sharpdisplay_framebuffer_get_pixels_in_byte_share_row(self);
+}
+
+STATIC bool sharpdisplay_framebuffer_get_reverse_pixels_in_byte(mp_obj_t self_in) {
+    sharpdisplay_framebuffer_obj_t *self = self_in;
+    return common_hal_sharpdisplay_framebuffer_get_reverse_pixels_in_byte(self);
+}
+
+STATIC int sharpdisplay_framebuffer_get_row_stride(mp_obj_t self_in) {
+    sharpdisplay_framebuffer_obj_t *self = self_in;
+    return common_hal_sharpdisplay_framebuffer_get_row_stride(self);
+}
+
+STATIC void sharpdisplay_framebuffer_swapbuffers(mp_obj_t self_in, uint8_t *dirty_row_bitmask) {
+    sharpdisplay_framebuffer_obj_t *self = self_in;
+    common_hal_sharpdisplay_framebuffer_swapbuffers(self, dirty_row_bitmask);
+}
+
+const framebuffer_p_t sharpdisplay_framebuffer_proto = {
+    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_framebuffer)
+    .deinit = sharpdisplay_framebuffer_deinit,
+    .get_bufinfo = sharpdisplay_framebuffer_get_bufinfo,
+    .get_color_depth = sharpdisplay_framebuffer_get_color_depth,
+    .get_height = sharpdisplay_framebuffer_get_height,
+    .get_width = sharpdisplay_framebuffer_get_width,
+    .swapbuffers = sharpdisplay_framebuffer_swapbuffers,
+
+    .get_first_pixel_offset = sharpdisplay_framebuffer_get_first_pixel_offset,
+    .get_pixels_in_byte_share_row = sharpdisplay_framebuffer_get_pixels_in_byte_share_row,
+    .get_reverse_pixels_in_byte = sharpdisplay_framebuffer_get_reverse_pixels_in_byte,
+    .get_row_stride = sharpdisplay_framebuffer_get_row_stride,
+};
+
+void common_hal_sharpdisplay_framebuffer_collect_ptrs(sharpdisplay_framebuffer_obj_t *self) {
+    gc_collect_ptr(self->framebuffer);
+    gc_collect_ptr(self->bus);
+    gc_collect_ptr(self->bufinfo.buf);
+}
diff --git a/shared-module/sharpdisplay/SharpMemoryFramebuffer.h b/shared-module/sharpdisplay/SharpMemoryFramebuffer.h
new file mode 100644
index 0000000000..8acacc94e1
--- /dev/null
+++ b/shared-module/sharpdisplay/SharpMemoryFramebuffer.h
@@ -0,0 +1,60 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "py/obj.h"
+#include "shared-bindings/busio/SPI.h"
+#include "shared-bindings/digitalio/DigitalInOut.h"
+#include "shared-module/framebufferio/FramebufferDisplay.h"
+
+typedef struct {
+    mp_obj_base_t base;
+    mp_obj_t framebuffer;
+    busio_spi_obj_t* bus;
+    busio_spi_obj_t inline_bus;
+    digitalio_digitalinout_obj_t chip_select;
+    mp_buffer_info_t bufinfo;
+
+    uint16_t width, height;
+    uint32_t baudrate;
+
+    bool full_refresh:1;
+} sharpdisplay_framebuffer_obj_t;
+
+void common_hal_sharpdisplay_framebuffer_construct(sharpdisplay_framebuffer_obj_t *self, busio_spi_obj_t *spi, mcu_pin_obj_t *chip_select, int baudrate, int width, int height);
+void common_hal_sharpdisplay_framebuffer_swap_buffers(sharpdisplay_framebuffer_obj_t *self, uint8_t *dirty_row_bitmask);
+void common_hal_sharpdisplay_framebuffer_deinit(sharpdisplay_framebuffer_obj_t *self);
+void common_hal_sharpdisplay_framebuffer_get_bufinfo(sharpdisplay_framebuffer_obj_t *self, mp_buffer_info_t *bufinfo);
+int common_hal_sharpdisplay_framebuffer_get_height(sharpdisplay_framebuffer_obj_t *self);
+int common_hal_sharpdisplay_framebuffer_get_width(sharpdisplay_framebuffer_obj_t *self);
+void common_hal_sharpdisplay_framebuffer_swap_buffers(sharpdisplay_framebuffer_obj_t *self, uint8_t *dirty_row_bitmask);
+void common_hal_sharpdisplay_framebuffer_reset(sharpdisplay_framebuffer_obj_t *self);
+void common_hal_sharpdisplay_framebuffer_reconstruct(sharpdisplay_framebuffer_obj_t *self);
+
+extern const framebuffer_p_t sharpdisplay_framebuffer_proto;
+
+void common_hal_sharpdisplay_framebuffer_collect_ptrs(sharpdisplay_framebuffer_obj_t*);
diff --git a/shared-module/sharpdisplay/__init__.c b/shared-module/sharpdisplay/__init__.c
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/shared-module/sharpdisplay/__init__.h b/shared-module/sharpdisplay/__init__.h
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/supervisor/shared/display.c b/supervisor/shared/display.c
index 9c074209b8..a86ef6396f 100644
--- a/supervisor/shared/display.c
+++ b/supervisor/shared/display.c
@@ -38,6 +38,11 @@
 #include "shared-module/displayio/__init__.h"
 #endif
 
+#if CIRCUITPY_SHARPDISPLAY
+#include "shared-bindings/sharpdisplay/SharpMemoryFramebuffer.h"
+#include "shared-module/sharpdisplay/SharpMemoryFramebuffer.h"
+#endif
+
 extern size_t blinka_bitmap_data[];
 extern displayio_bitmap_t blinka_bitmap;
 extern displayio_group_t circuitpython_splash;
@@ -116,15 +121,21 @@ void supervisor_display_move_memory(void) {
         grid->inline_tiles = false;
     }
     MP_STATE_VM(terminal_tilegrid_tiles) = NULL;
-    #if CIRCUITPY_RGBMATRIX
     for (uint8_t i = 0; i < CIRCUITPY_DISPLAY_LIMIT; i++) {
-        if (displays[i].rgbmatrix.base.type == &rgbmatrix_RGBMatrix_type) {
-            rgbmatrix_rgbmatrix_obj_t * pm = &displays[i].rgbmatrix;
+        #if CIRCUITPY_RGBMATRIX
+            if (displays[i].rgbmatrix.base.type == &rgbmatrix_RGBMatrix_type) {
+                rgbmatrix_rgbmatrix_obj_t * pm = &displays[i].rgbmatrix;
                 common_hal_rgbmatrix_rgbmatrix_reconstruct(pm, NULL);
-        }
+            }
+        #endif
+        #if CIRCUITPY_SHARPDISPLAY
+            if (displays[i].bus_base.type == &sharpdisplay_framebuffer_type) {
+                sharpdisplay_framebuffer_obj_t * sharp = &displays[i].sharpdisplay;
+                common_hal_sharpdisplay_framebuffer_reconstruct(sharp);
+            }
+        #endif
     }
     #endif
-    #endif
 }
 
 size_t blinka_bitmap_data[32] = {

From 65f91f69ccdb3489f5ba649c939b8e3e96cc74e4 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Tue, 11 Aug 2020 15:37:10 -0500
Subject: [PATCH 13/19] make translate

---
 locale/circuitpython.pot | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/locale/circuitpython.pot b/locale/circuitpython.pot
index 510facece6..32b5df5ee3 100644
--- a/locale/circuitpython.pot
+++ b/locale/circuitpython.pot
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2020-08-10 12:54-0500\n"
+"POT-Creation-Date: 2020-08-11 15:37-0500\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -823,6 +823,11 @@ msgstr ""
 msgid "File exists"
 msgstr ""
 
+#: shared-module/framebufferio/FramebufferDisplay.c
+#, c-format
+msgid "Framebuffer requires %d bytes"
+msgstr ""
+
 #: ports/atmel-samd/common-hal/frequencyio/FrequencyIn.c
 msgid "Frequency captured is above capability. Capture Paused."
 msgstr ""

From 759ded9c38390c6d4328bd34aa211499b7e9f4f6 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Wed, 12 Aug 2020 07:39:12 -0500
Subject: [PATCH 14/19] Fix build errors when SHARPDISPLAY && !RGBMATRIX

---
 shared-module/displayio/__init__.c | 4 ++--
 supervisor/shared/display.c        | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/shared-module/displayio/__init__.c b/shared-module/displayio/__init__.c
index e52ec5b9e3..5afcba35ec 100644
--- a/shared-module/displayio/__init__.c
+++ b/shared-module/displayio/__init__.c
@@ -107,7 +107,7 @@ void common_hal_displayio_release_displays(void) {
             common_hal_displayio_i2cdisplay_deinit(&displays[i].i2cdisplay_bus);
         } else if (bus_type == &displayio_parallelbus_type) {
             common_hal_displayio_parallelbus_deinit(&displays[i].parallel_bus);
-#if CIRCUITPY_FRAMEBUFFERIO
+#if CIRCUITPY_RGBMATRIX
         } else if (bus_type == &rgbmatrix_RGBMatrix_type) {
             common_hal_rgbmatrix_rgbmatrix_deinit(&displays[i].rgbmatrix);
 #endif
@@ -222,7 +222,7 @@ void displayio_gc_collect(void) {
         }
 #endif
 #if CIRCUITPY_SHARPDISPLAY
-        if (displays[i].rgbmatrix.base.type == &sharpdisplay_framebuffer_type) {
+        if (displays[i].bus_base.type == &sharpdisplay_framebuffer_type) {
             common_hal_sharpdisplay_framebuffer_collect_ptrs(&displays[i].sharpdisplay);
         }
 #endif
diff --git a/supervisor/shared/display.c b/supervisor/shared/display.c
index a86ef6396f..08dd71404b 100644
--- a/supervisor/shared/display.c
+++ b/supervisor/shared/display.c
@@ -39,6 +39,7 @@
 #endif
 
 #if CIRCUITPY_SHARPDISPLAY
+#include "shared-module/displayio/__init__.h"
 #include "shared-bindings/sharpdisplay/SharpMemoryFramebuffer.h"
 #include "shared-module/sharpdisplay/SharpMemoryFramebuffer.h"
 #endif

From cff448205f165dfd5ec40cc5b336decff045d4cd Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Wed, 12 Aug 2020 07:39:28 -0500
Subject: [PATCH 15/19] Don't define SHARPDISPLAY when !DISPLAYIO

.. even if FULL_BUILD
---
 py/circuitpy_mpconfig.mk | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/py/circuitpy_mpconfig.mk b/py/circuitpy_mpconfig.mk
index 1ba71fa023..56060fa594 100644
--- a/py/circuitpy_mpconfig.mk
+++ b/py/circuitpy_mpconfig.mk
@@ -95,7 +95,11 @@ CFLAGS += -DCIRCUITPY_COUNTIO=$(CIRCUITPY_COUNTIO)
 CIRCUITPY_DISPLAYIO ?= $(CIRCUITPY_FULL_BUILD)
 CFLAGS += -DCIRCUITPY_DISPLAYIO=$(CIRCUITPY_DISPLAYIO)
 
+ifeq ($(CIRCUITPY_DISPLAYIO),1)
 CIRCUITPY_FRAMEBUFFERIO ?= $(CIRCUITPY_FULL_BUILD)
+else
+CIRCUITPY_FRAMEBUFFERIO ?= 0
+endif
 CFLAGS += -DCIRCUITPY_FRAMEBUFFERIO=$(CIRCUITPY_FRAMEBUFFERIO)
 
 CIRCUITPY_VECTORIO ?= $(CIRCUITPY_DISPLAYIO)

From 454e616d13e6db762271b9e1ea8191407228e0ae Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Wed, 12 Aug 2020 10:46:56 -0500
Subject: [PATCH 16/19] atmel-samd: disable FRAMEBUFFERIO on samd21

.. this disables SHARPMEMORY as well.
---
 ports/atmel-samd/mpconfigport.mk | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/ports/atmel-samd/mpconfigport.mk b/ports/atmel-samd/mpconfigport.mk
index e4cf9ca833..5788a160b1 100644
--- a/ports/atmel-samd/mpconfigport.mk
+++ b/ports/atmel-samd/mpconfigport.mk
@@ -39,6 +39,9 @@ endif
 
 CIRCUITPY_SDCARDIO ?= 0
 
+# Not enough RAM for framebuffers
+CIRCUITPY_FRAMEBUFFERIO ?= 0
+
 # SAMD21 needs separate endpoint pairs for MSC BULK IN and BULK OUT, otherwise it's erratic.
 USB_MSC_EP_NUM_OUT = 1
 

From d61f66d173c956b10679e83b93d7f84fbc6f0bb4 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Wed, 12 Aug 2020 12:50:08 -0500
Subject: [PATCH 17/19] Update shared-module/framebufferio/FramebufferDisplay.h

Co-authored-by: Scott Shawcroft <scott@tannewt.org>
---
 shared-module/framebufferio/FramebufferDisplay.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/shared-module/framebufferio/FramebufferDisplay.h b/shared-module/framebufferio/FramebufferDisplay.h
index 111c9f670d..89df0d27c1 100644
--- a/shared-module/framebufferio/FramebufferDisplay.h
+++ b/shared-module/framebufferio/FramebufferDisplay.h
@@ -48,7 +48,8 @@ typedef struct {
     uint64_t last_refresh_call;
     uint16_t native_frames_per_second;
     uint16_t native_ms_per_frame;
-    uint16_t first_pixel_offset, row_stride;
+    uint16_t first_pixel_offset;
+    uint16_t row_stride;
     bool auto_refresh;
     bool first_manual_refresh;
 } framebufferio_framebufferdisplay_obj_t;

From 06f6cd067dbf3c3f01d6f85445a190ee18e58b01 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Wed, 12 Aug 2020 12:51:35 -0500
Subject: [PATCH 18/19] nrf: Improve commenting about disabled warnings

---
 ports/nrf/Makefile | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/ports/nrf/Makefile b/ports/nrf/Makefile
index d1745a70ef..3fef68e88e 100755
--- a/ports/nrf/Makefile
+++ b/ports/nrf/Makefile
@@ -100,8 +100,6 @@ CFLAGS += $(OPTIMIZATION_FLAGS)
 CFLAGS += $(INC) -Wall -Werror -std=gnu11 -nostdlib -fshort-enums $(BASE_CFLAGS) $(CFLAGS_MOD) $(COPT)
 
 # Undo some warnings.
-## nrfx uses undefined preprocessor variables quite casually, so we can't do warning checks for these.
-#CFLAGS += -Wno-undef
 # nrfx does casts that increase alignment requirements.
 CFLAGS += -Wno-cast-align
 
@@ -240,6 +238,9 @@ endif
 OBJ += $(addprefix $(BUILD)/, $(SRC_S:.s=.o))
 OBJ += $(addprefix $(BUILD)/, $(SRC_MOD:.c=.o))
 
+# nrfx uses undefined preprocessor variables quite casually, so we can't do
+# warning checks for these.  Happily, we've confined the offenders to the NRFX
+# source files themselves.
 $(addprefix $(BUILD)/, $(SRC_NRFX:.c=.o)): CFLAGS += -Wno-undef
 
 $(BUILD)/$(FATFS_DIR)/ff.o: COPT += -Os

From 195c0ea986fd44f3b56cc57f23e8259df1e18202 Mon Sep 17 00:00:00 2001
From: Jeff Epler <jepler@gmail.com>
Date: Wed, 12 Aug 2020 13:01:43 -0500
Subject: [PATCH 19/19] sharpdisplay: Make PARTIAL_UPDATES unconditional

---
 shared-module/sharpdisplay/SharpMemoryFramebuffer.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/shared-module/sharpdisplay/SharpMemoryFramebuffer.c b/shared-module/sharpdisplay/SharpMemoryFramebuffer.c
index ac9c225729..71e00d7f01 100644
--- a/shared-module/sharpdisplay/SharpMemoryFramebuffer.c
+++ b/shared-module/sharpdisplay/SharpMemoryFramebuffer.c
@@ -183,8 +183,6 @@ void common_hal_sharpdisplay_framebuffer_swapbuffers(sharpdisplay_framebuffer_ob
     uint8_t *data = self->bufinfo.buf;
     data[0] ^= SHARPMEM_BIT_VCOM_LSB;
 
-#define PARTIAL_UPDATES (1)
-#if PARTIAL_UPDATES
     common_hal_busio_spi_write(self->bus, data++, 1);
 
     // output each changed row
@@ -198,9 +196,6 @@ void common_hal_sharpdisplay_framebuffer_swapbuffers(sharpdisplay_framebuffer_ob
 
     // output a trailing zero
     common_hal_busio_spi_write(self->bus, data, 1);
-#else
-    common_hal_busio_spi_write(self->bus, data, self->bufinfo.len);
-#endif
 
     // set chip select low
     common_hal_digitalio_digitalinout_set_value(&self->chip_select, false);