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Merge pull request #1161 from hathach/nrf52_neopixel

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Nrf52 neopixel
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Dan Halbert 2018-09-05 08:09:07 -04:00 committed by GitHub
commit a0872e8761
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5 changed files with 283 additions and 2 deletions
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1
ports/nrf/Makefile
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@ -141,6 +141,7 @@ SRC_COMMON_HAL += \
microcontroller/__init__.c \
microcontroller/Pin.c \
microcontroller/Processor.c \
neopixel_write/__init__.c \
os/__init__.c \
time/__init__.c \
analogio/__init__.c \

267
ports/nrf/common-hal/neopixel_write/__init__.c Normal file
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@ -0,0 +1,267 @@
/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2018 hathach 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/mphal.h"
#include "shared-bindings/neopixel_write/__init__.h"
#include "nrf_pwm.h"
// https://github.com/adafruit/Adafruit_NeoPixel/blob/master/Adafruit_NeoPixel.cpp
// [[[Begin of the Neopixel NRF52 EasyDMA implementation
// by the Hackerspace San Salvador]]]
// This technique uses the PWM peripheral on the NRF52. The PWM uses the
// EasyDMA feature included on the chip. This technique loads the duty
// cycle configuration for each cycle when the PWM is enabled. For this
// to work we need to store a 16 bit configuration for each bit of the
// RGB(W) values in the pixel buffer.
// Comparator values for the PWM were hand picked and are guaranteed to
// be 100% organic to preserve freshness and high accuracy. Current
// parameters are:
// * PWM Clock: 16Mhz
// * Minimum step time: 62.5ns
// * Time for zero in high (T0H): 0.31ms
// * Time for one in high (T1H): 0.75ms
// * Cycle time: 1.25us
// * Frequency: 800Khz
// For 400Khz we just double the calculated times.
// ---------- BEGIN Constants for the EasyDMA implementation -----------
// The PWM starts the duty cycle in LOW. To start with HIGH we
// need to set the 15th bit on each register.
// WS2812 (rev A) timing is 0.35 and 0.7us
//#define MAGIC_T0H 5UL | (0x8000) // 0.3125us
//#define MAGIC_T1H 12UL | (0x8000) // 0.75us
// WS2812B (rev B) timing is 0.4 and 0.8 us
#define MAGIC_T0H 6UL | (0x8000) // 0.375us
#define MAGIC_T1H 13UL | (0x8000) // 0.8125us
#define CTOPVAL 20UL // 1.25us
// ---------- END Constants for the EasyDMA implementation -------------
//
// If there is no device available an alternative cycle-counter
// implementation is tried.
// The nRF52832 runs with a fixed clock of 64Mhz. The alternative
// implementation is the same as the one used for the Teensy 3.0/1/2 but
// with the Nordic SDK HAL & registers syntax.
// The number of cycles was hand picked and is guaranteed to be 100%
// organic to preserve freshness and high accuracy.
// ---------- BEGIN Constants for cycle counter implementation ---------
#define CYCLES_800_T0H 18 // ~0.36 uS
#define CYCLES_800_T1H 41 // ~0.76 uS
#define CYCLES_800 71 // ~1.25 uS
// ---------- END of Constants for cycle counter implementation --------
// find a free PWM device, which is not enabled and has no connected pins
static NRF_PWM_Type* find_free_pwm (void) {
NRF_PWM_Type* PWM[] = {
NRF_PWM0, NRF_PWM1, NRF_PWM2
#ifdef NRF_PWM3
, NRF_PWM3
#endif
};
for ( int device = 0; device < ARRAY_SIZE(PWM); device++ ) {
if ( (PWM[device]->ENABLE == 0) &&
(PWM[device]->PSEL.OUT[0] & PWM_PSEL_OUT_CONNECT_Msk) && (PWM[device]->PSEL.OUT[1] & PWM_PSEL_OUT_CONNECT_Msk) &&
(PWM[device]->PSEL.OUT[2] & PWM_PSEL_OUT_CONNECT_Msk) && (PWM[device]->PSEL.OUT[3] & PWM_PSEL_OUT_CONNECT_Msk) ) {
return PWM[device];
}
}
return NULL;
}
void common_hal_neopixel_write (const digitalio_digitalinout_obj_t* digitalinout, uint8_t *pixels, uint32_t numBytes) {
// To support both the SoftDevice + Neopixels we use the EasyDMA
// feature from the NRF25. However this technique implies to
// generate a pattern and store it on the memory. The actual
// memory used in bytes corresponds to the following formula:
// totalMem = numBytes*8*2+(2*2)
// The two additional bytes at the end are needed to reset the
// sequence.
//
// If there is not enough memory, we will fall back to cycle counter
// using DWT
uint32_t pattern_size = numBytes * 8 * sizeof(uint16_t) + 2 * sizeof(uint16_t);
uint16_t* pixels_pattern = NULL;
NRF_PWM_Type* pwm = find_free_pwm();
// only malloc if there is PWM device available
if ( pwm != NULL ) {
pixels_pattern = (uint16_t *) m_malloc(pattern_size, false);
}
// Use the identified device to choose the implementation
// If a PWM device is available use DMA
if ( (pixels_pattern != NULL) && (pwm != NULL) ) {
uint16_t pos = 0; // bit position
for ( uint16_t n = 0; n < numBytes; n++ ) {
uint8_t pix = pixels[n];
for ( uint8_t mask = 0x80, i = 0; mask > 0; mask >>= 1, i++ ) {
pixels_pattern[pos] = (pix & mask) ? MAGIC_T1H : MAGIC_T0H;
pos++;
}
}
// Zero padding to indicate the end of sequence
pixels_pattern[++pos] = 0 | (0x8000); // Seq end
pixels_pattern[++pos] = 0 | (0x8000); // Seq end
// Set the wave mode to count UP
// Set the PWM to use the 16MHz clock
// Setting of the maximum count
// but keeping it on 16Mhz allows for more granularity just
// in case someone wants to do more fine-tuning of the timing.
nrf_pwm_configure(pwm, NRF_PWM_CLK_16MHz, NRF_PWM_MODE_UP, CTOPVAL);
// Disable loops, we want the sequence to repeat only once
nrf_pwm_loop_set(pwm, 0);
// On the "Common" setting the PWM uses the same pattern for the
// for supported sequences. The pattern is stored on half-word of 16bits
nrf_pwm_decoder_set(pwm, PWM_DECODER_LOAD_Common, PWM_DECODER_MODE_RefreshCount);
// Pointer to the memory storing the pattern
nrf_pwm_seq_ptr_set(pwm, 0, pixels_pattern);
// Calculation of the number of steps loaded from memory.
nrf_pwm_seq_cnt_set(pwm, 0, pattern_size / sizeof(uint16_t));
// The following settings are ignored with the current config.
nrf_pwm_seq_refresh_set(pwm, 0, 0);
nrf_pwm_seq_end_delay_set(pwm, 0, 0);
// The Neopixel implementation is a blocking algorithm. DMA
// allows for non-blocking operation. To "simulate" a blocking
// operation we enable the interruption for the end of sequence
// and block the execution thread until the event flag is set by
// the peripheral.
// pwm->INTEN |= (PWM_INTEN_SEQEND0_Enabled<<PWM_INTEN_SEQEND0_Pos);
// PSEL must be configured before enabling PWM
nrf_pwm_pins_set(pwm, (uint32_t[]) {digitalinout->pin->port*32 + digitalinout->pin->pin, 0xFFFFFFFFUL, 0xFFFFFFFFUL, 0xFFFFFFFFUL} );
// Enable the PWM
nrf_pwm_enable(pwm);
// After all of this and many hours of reading the documentation
// we are ready to start the sequence...
nrf_pwm_event_clear(pwm, NRF_PWM_EVENT_SEQEND0);
nrf_pwm_task_trigger(pwm, NRF_PWM_TASK_SEQSTART0);
// But we have to wait for the flag to be set.
while ( !nrf_pwm_event_check(pwm, NRF_PWM_EVENT_SEQEND0) ) {
#ifdef MICROPY_VM_HOOK_LOOP
MICROPY_VM_HOOK_LOOP
#endif
}
// Before leave we clear the flag for the event.
nrf_pwm_event_clear(pwm, NRF_PWM_EVENT_SEQEND0);
// We need to disable the device and disconnect
// all the outputs before leave or the device will not
// be selected on the next call.
// TODO: Check if disabling the device causes performance issues.
nrf_pwm_disable(pwm);
nrf_pwm_pins_set(pwm, (uint32_t[]) {0xFFFFFFFFUL, 0xFFFFFFFFUL, 0xFFFFFFFFUL, 0xFFFFFFFFUL} );
m_free(pixels_pattern);
} // End of DMA implementation
// ---------------------------------------------------------------------
else {
// Fall back to DWT
// If you are using the Bluetooth SoftDevice we advise you to not disable
// the interrupts. Disabling the interrupts even for short periods of time
// causes the SoftDevice to stop working.
// Disable the interrupts only in cases where you need high performance for
// the LEDs and if you are not using the EasyDMA feature.
__disable_irq();
#ifdef NRF_P1
NRF_GPIO_Type* port = ( digitalinout->pin->port ? NRF_P1 : NRF_P0 );
#else
NRF_GPIO_Type* port = NRF_P0;
#endif
uint32_t pinMask = ( 1UL << digitalinout->pin->pin );
uint32_t CYCLES_X00 = CYCLES_800;
uint32_t CYCLES_X00_T1H = CYCLES_800_T1H;
uint32_t CYCLES_X00_T0H = CYCLES_800_T0H;
// Enable DWT in debug core
CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk;
DWT->CTRL |= DWT_CTRL_CYCCNTENA_Msk;
// Tries to re-send the frame if is interrupted by the SoftDevice.
while ( 1 ) {
uint8_t *p = pixels;
uint32_t cycStart = DWT->CYCCNT;
uint32_t cyc = 0;
for ( uint16_t n = 0; n < numBytes; n++ ) {
uint8_t pix = *p++;
for ( uint8_t mask = 0x80; mask; mask >>= 1 ) {
while ( DWT->CYCCNT - cyc < CYCLES_X00 )
;
cyc = DWT->CYCCNT;
port->OUTSET |= pinMask;
if ( pix & mask ) {
while ( DWT->CYCCNT - cyc < CYCLES_X00_T1H )
;
} else {
while ( DWT->CYCCNT - cyc < CYCLES_X00_T0H )
;
}
port->OUTCLR |= pinMask;
}
}
while ( DWT->CYCCNT - cyc < CYCLES_X00 )
;
// If total time longer than 25%, resend the whole data.
// Since we are likely to be interrupted by SoftDevice
if ( (DWT->CYCCNT - cycStart) < (8 * numBytes * ((CYCLES_X00 * 5) / 4)) ) {
break;
}
// re-send need 300us delay
mp_hal_delay_us(300);
}
// Enable interrupts again
__enable_irq();
}
}

2
ports/nrf/mpconfigport.h
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@ -180,6 +180,7 @@ extern const struct _mp_obj_module_t struct_module;
extern const struct _mp_obj_module_t time_module;
extern const struct _mp_obj_module_t supervisor_module;
extern const struct _mp_obj_module_t gamepad_module;
extern const struct _mp_obj_module_t neopixel_write_module;
extern const struct _mp_obj_module_t usb_hid_module;
extern const struct _mp_obj_module_t bleio_module;
@ -210,6 +211,7 @@ extern const struct _mp_obj_module_t mp_module_ubluepy;
{ MP_OBJ_NEW_QSTR (MP_QSTR_digitalio ), (mp_obj_t)&digitalio_module }, \
{ MP_OBJ_NEW_QSTR (MP_QSTR_pulseio ), (mp_obj_t)&pulseio_module }, \
{ MP_OBJ_NEW_QSTR (MP_QSTR_microcontroller ), (mp_obj_t)&microcontroller_module }, \
{ MP_OBJ_NEW_QSTR (MP_QSTR_neopixel_write ), (mp_obj_t)&neopixel_write_module }, \
{ MP_OBJ_NEW_QSTR (MP_QSTR_bitbangio ), (mp_obj_t)&bitbangio_module }, \
{ MP_OBJ_NEW_QSTR (MP_QSTR_os ), (mp_obj_t)&os_module }, \
{ MP_OBJ_NEW_QSTR (MP_QSTR_random ), (mp_obj_t)&random_module }, \

11
ports/nrf/nrfx_config.h
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@ -34,4 +34,15 @@
#define NRFX_UART_DEFAULT_CONFIG_PARITY NRF_UART_PARITY_EXCLUDED
#define NRFX_UART_DEFAULT_CONFIG_BAUDRATE NRF_UART_BAUDRATE_115200
// PWM
#define NRFX_PWM0_ENABLED 1
#define NRFX_PWM1_ENABLED 1
#define NRFX_PWM2_ENABLED 1
#ifdef NRF_PWM3
#define NRFX_PWM3_ENABLED 1
#else
#define NRFX_PWM3_ENABLED 0
#endif
#endif

4
ports/nrf/usb/usb.c
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@ -130,8 +130,8 @@ uint32_t tusb_hal_millis(void) {
void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts) {
(void) itf; // interface ID, not used
// disconnected event
if ( !dtr && !rts )
// DTR = false is counted as disconnected
if ( !dtr )
{
cdc_line_coding_t coding;
tud_cdc_get_line_coding(&coding);