drivers: Add SSD1306 OLED driver, with I2C and SPI interfaces.

drivers/display/ssd1306.py

@@ -0,0 +1,145 @@
+# MicroPython SSD1306 OLED driver, I2C and SPI interfaces
+
+import time
+import framebuf
+
+# register definitions
+SET_CONTRAST        = const(0x81)
+SET_ENTIRE_ON       = const(0xa4)
+SET_NORM_INV        = const(0xa6)
+SET_DISP            = const(0xae)
+SET_MEM_ADDR        = const(0x20)
+SET_COL_ADDR        = const(0x21)
+SET_PAGE_ADDR       = const(0x22)
+SET_DISP_START_LINE = const(0x40)
+SET_SEG_REMAP       = const(0xa0)
+SET_MUX_RATIO       = const(0xa8)
+SET_COM_OUT_DIR     = const(0xc0)
+SET_DISP_OFFSET     = const(0xd3)
+SET_COM_PIN_CFG     = const(0xda)
+SET_DISP_CLK_DIV    = const(0xd5)
+SET_PRECHARGE       = const(0xd9)
+SET_VCOM_DESEL      = const(0xdb)
+SET_CHARGE_PUMP     = const(0x8d)
+
+class SSD1306:
+    def __init__(self, height, external_vcc):
+        self.width = 128
+        self.height = height
+        self.external_vcc = external_vcc
+        self.pages = self.height // 8
+        self.buffer = bytearray(self.pages * self.width)
+        self.framebuf = framebuf.FrameBuffer1(self.buffer, self.width, self.height)
+        self.poweron()
+        self.init_display()
+
+    def init_display(self):
+        for cmd in (
+            SET_DISP | 0x00, # off
+            # address setting
+            SET_MEM_ADDR, 0x00, # horizontal
+            # resolution and layout
+            SET_DISP_START_LINE | 0x00,
+            SET_SEG_REMAP | 0x01, # column addr 127 mapped to SEG0
+            SET_MUX_RATIO, self.height - 1,
+            SET_COM_OUT_DIR | 0x08, # scan from COM[N] to COM0
+            SET_DISP_OFFSET, 0x00,
+            SET_COM_PIN_CFG, 0x02 if self.height == 32 else 0x12,
+            # timing and driving scheme
+            SET_DISP_CLK_DIV, 0x80,
+            SET_PRECHARGE, 0x22 if self.external_vcc else 0xf1,
+            SET_VCOM_DESEL, 0x30, # 0.83*Vcc
+            # display
+            SET_CONTRAST, 0xff, # maximum
+            SET_ENTIRE_ON, # output follows RAM contents
+            SET_NORM_INV, # not inverted
+            # charge pump
+            SET_CHARGE_PUMP, 0x10 if self.external_vcc else 0x14,
+            SET_DISP | 0x01): # on
+            self.write_cmd(cmd)
+        self.fill(0)
+        self.show()
+
+    def poweroff(self):
+        self.write_cmd(SET_DISP | 0x00)
+
+    def contrast(self, contrast):
+        self.write_cmd(SET_CONTRAST)
+        self.write_cmd(contrast)
+
+    def invert(self, invert):
+        self.write_cmd(SET_NORM_INV | (invert & 1))
+
+    def show(self):
+        self.write_cmd(SET_COL_ADDR)
+        self.write_cmd(0)
+        self.write_cmd(self.width - 1)
+        self.write_cmd(SET_PAGE_ADDR)
+        self.write_cmd(0)
+        self.write_cmd(self.pages - 1)
+        self.write_data(self.buffer)
+
+    def fill(self, col):
+        self.framebuf.fill(col)
+
+    def pixel(self, x, y, col):
+        self.framebuf.pixel(x, y, col)
+
+    def scroll(self, dx, dy):
+        self.framebuf.scroll(dx, dy)
+
+    def text(self, string, x, y, col=1):
+        self.framebuf.text(string, x, y, col)
+
+class SSD1306_I2C(SSD1306):
+    def __init__(self, height, i2c, addr=0x3c, external_vcc=False):
+        self.i2c = i2c
+        self.addr = addr
+        self.temp = bytearray(2)
+        super().__init__(height, external_vcc)
+
+    def write_cmd(self, cmd):
+        self.temp[0] = 0x80 # Co=1, D/C#=0
+        self.temp[1] = cmd
+        self.i2c.writeto(self.addr, self.temp)
+
+    def write_data(self, buf):
+        self.temp[0] = self.addr << 1
+        self.temp[1] = 0x40 # Co=0, D/C#=1
+        self.i2c.start()
+        self.i2c.write(self.temp)
+        self.i2c.write(buf)
+        self.i2c.stop()
+
+    def poweron(self):
+        pass
+
+# TODO convert this class to use the new hardware API
+class SSD1306_SPI(SSD1306):
+    def __init__(self, height, spi, dc, res, cs=None, external_vcc=False):
+        rate = 10 * 1024 * 1024
+        spi.init(spi.MASTER, baudrate=rate, polarity=0, phase=0)
+        dc.init(dc.OUT, dc.PULL_NONE, value=0)
+        res.init(res.OUT, dc.PULL_NONE, value=0)
+        if cs is not None:
+            cs.init(cs.OUT, cs.PULL_NONE, value=0)
+        self.spi = spi
+        self.dc = dc
+        self.res = res
+        super().__init__(height, external_vcc)
+
+    def write_cmd(self, cmd):
+        self.dc.low()
+        self.spi.send(cmd)
+
+    def write_data(self, buf):
+        self.dc.high()
+        self.spi.send(buf)
+
+    def poweron(self):
+        self.res.high()
+        time.sleep_ms(1)
+        self.res.low()
+        time.sleep_ms(10)
+        self.res.high()
+        time.sleep_ms(10)