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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2019 Lucian Copeland 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 "shared-bindings/neopixel_write/__init__.h"
#include "py/mperrno.h"
#include "py/mphal.h"
#include "py/runtime.h"
#include "common-hal/microcontroller/Pin.h"
#include "stm32f4xx_hal.h"
#include "stm32f4xx_ll_gpio.h"
#include "supervisor/port.h"
uint64_t next_start_raw_ticks = 0;
// sysclock divisors
#define MAGIC_800_INT 900000 // ~1.11 us -> 1.2 field
#define MAGIC_800_T0H 2800000 // ~0.36 us -> 0.44 field
#define MAGIC_800_T1H 1350000 // ~0.74 us -> 0.84 field
#pragma GCC push_options
#pragma GCC optimize ("Os")
void common_hal_neopixel_write(const digitalio_digitalinout_obj_t *digitalinout, uint8_t *pixels,
uint32_t numBytes) {
uint8_t *p = pixels, *end = p + numBytes, pix = *p++, mask = 0x80;
uint32_t start = 0;
uint32_t cyc = 0;
// assumes 800_000Hz frequency
// Theoretical values here are 800_000 -> 1.25us, 2500000->0.4us, 1250000->0.8us
// TODO: try to get dynamic weighting working again
uint32_t sys_freq = HAL_RCC_GetSysClockFreq();
uint32_t interval = sys_freq / MAGIC_800_INT;
uint32_t t0 = (sys_freq / MAGIC_800_T0H);
uint32_t t1 = (sys_freq / MAGIC_800_T1H);
// Wait to make sure we don't append onto the last transmission. This should only be a tick or
// two.
while (port_get_raw_ticks(NULL) < next_start_raw_ticks) {
}
GPIO_TypeDef *p_port = pin_port(digitalinout->pin->port);
uint32_t p_mask = pin_mask(digitalinout->pin->number);
__disable_irq();
// Enable DWT in debug core. Useable when interrupts disabled, as opposed to Systick->VAL
CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk;
DWT->CTRL |= DWT_CTRL_CYCCNTENA_Msk;
DWT->CYCCNT = 0;
for (;;) {
cyc = (pix & mask) ? t1 : t0;
start = DWT->CYCCNT;
LL_GPIO_SetOutputPin(p_port, p_mask);
while ((DWT->CYCCNT - start) < cyc) {
;
}
LL_GPIO_ResetOutputPin(p_port, p_mask);
while ((DWT->CYCCNT - start) < interval) {
;
}
if (!(mask >>= 1)) {
if (p >= end) {
break;
}
pix = *p++;
mask = 0x80;
}
}
// Enable interrupts again
__enable_irq();
// Update the next start.
next_start_raw_ticks = port_get_raw_ticks(NULL) + 4;
}
#pragma GCC pop_options
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