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