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// Original version from https://github.com/adafruit/Adafruit_NeoPixel
// Modifications by dpgeorge to support auto-CPU-frequency detection
// This is a mash-up of the Due show() code + insights from Michael Miller's
// ESP8266 work for the NeoPixelBus library: github.com/Makuna/NeoPixelBus
// Needs to be a separate .c file to enforce ICACHE_RAM_ATTR execution.
#include "py/mpconfig.h"
#include "py/mphal.h"
#include "modesp.h"
void IRAM_ATTR esp_neopixel_write(uint8_t pin, uint8_t *pixels, uint32_t numBytes, uint8_t timing) {
uint8_t *p, *end, pix, mask;
uint32_t t, time0, time1, period, c, startTime, pinMask;
pinMask = 1 << pin;
p = pixels;
end = p + numBytes;
pix = *p++;
mask = 0x80;
startTime = 0;
uint32_t fcpu = ets_get_cpu_frequency() * 1000000;
if (timing == 1) {
// 800 KHz
time0 = (fcpu * 0.35) / 1000000; // 0.35us
time1 = (fcpu * 0.8) / 1000000; // 0.8us
period = (fcpu * 1.25) / 1000000; // 1.25us per bit
} else {
// 400 KHz
time0 = (fcpu * 0.5) / 1000000; // 0.35us
time1 = (fcpu * 1.2) / 1000000; // 0.8us
period = (fcpu * 2.5) / 1000000; // 1.25us per bit
}
uint32_t irq_state = mp_hal_quiet_timing_enter();
for (t = time0;; t = time0) {
if (pix & mask) {
t = time1; // Bit high duration
}
while (((c = mp_hal_ticks_cpu()) - startTime) < period) {
; // Wait for bit start
}
GPIO_REG_WRITE(GPIO_OUT_W1TS_REG, pinMask); // Set high
startTime = c; // Save start time
while (((c = mp_hal_ticks_cpu()) - startTime) < t) {
; // Wait high duration
}
GPIO_REG_WRITE(GPIO_OUT_W1TC_REG, pinMask); // Set low
if (!(mask >>= 1)) { // Next bit/byte
if (p >= end) {
break;
}
pix = *p++;
mask = 0x80;
}
}
while ((mp_hal_ticks_cpu() - startTime) < period) {
; // Wait for last bit
}
mp_hal_quiet_timing_exit(irq_state);
}
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