96 lines
3.2 KiB
C
96 lines
3.2 KiB
C
#include "quantum.h"
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#include "ws2812.h"
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#include "ch.h"
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#include "hal.h"
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/* Adapted from https://github.com/bigjosh/SimpleNeoPixelDemo/ */
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#ifndef NOP_FUDGE
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# if defined(STM32F0XX) || defined(STM32F1XX) || defined(STM32F3XX) || defined(STM32F4XX) || defined(STM32L0XX)
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# define NOP_FUDGE 0.4
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# else
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# error("NOP_FUDGE configuration required")
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# define NOP_FUDGE 1 // this just pleases the compile so the above error is easier to spot
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# endif
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#endif
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#define NUMBER_NOPS 6
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#define CYCLES_PER_SEC (STM32_SYSCLK / NUMBER_NOPS * NOP_FUDGE)
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#define NS_PER_SEC (1000000000L) // Note that this has to be SIGNED since we want to be able to check for negative values of derivatives
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#define NS_PER_CYCLE (NS_PER_SEC / CYCLES_PER_SEC)
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#define NS_TO_CYCLES(n) ((n) / NS_PER_CYCLE)
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#define wait_ns(x) \
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do { \
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for (int i = 0; i < NS_TO_CYCLES(x); i++) { \
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__asm__ volatile("nop\n\t" \
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"nop\n\t" \
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"nop\n\t" \
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"nop\n\t" \
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"nop\n\t" \
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"nop\n\t"); \
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} \
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} while (0)
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// These are the timing constraints taken mostly from the WS2812 datasheets
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// These are chosen to be conservative and avoid problems rather than for maximum throughput
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#define T1H 900 // Width of a 1 bit in ns
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#define T1L (1250 - T1H) // Width of a 1 bit in ns
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#define T0H 350 // Width of a 0 bit in ns
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#define T0L (1250 - T0H) // Width of a 0 bit in ns
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// The reset gap can be 6000 ns, but depending on the LED strip it may have to be increased
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// to values like 600000 ns. If it is too small, the pixels will show nothing most of the time.
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#define RES 10000 // Width of the low gap between bits to cause a frame to latch
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void sendByte(uint8_t byte) {
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// WS2812 protocol wants most significant bits first
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for (unsigned char bit = 0; bit < 8; bit++) {
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bool is_one = byte & (1 << (7 - bit));
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// using something like wait_ns(is_one ? T1L : T0L) here throws off timings
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if (is_one) {
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// 1
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writePinHigh(RGB_DI_PIN);
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wait_ns(T1H);
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writePinLow(RGB_DI_PIN);
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wait_ns(T1L);
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} else {
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// 0
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writePinHigh(RGB_DI_PIN);
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wait_ns(T0H);
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writePinLow(RGB_DI_PIN);
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wait_ns(T0L);
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}
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}
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}
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void ws2812_init(void) { setPinOutput(RGB_DI_PIN); }
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// Setleds for standard RGB
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void ws2812_setleds(LED_TYPE *ledarray, uint16_t leds) {
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static bool s_init = false;
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if (!s_init) {
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ws2812_init();
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s_init = true;
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}
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// this code is very time dependent, so we need to disable interrupts
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chSysLock();
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for (uint8_t i = 0; i < leds; i++) {
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// WS2812 protocol dictates grb order
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sendByte(ledarray[i].g);
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sendByte(ledarray[i].r);
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sendByte(ledarray[i].b);
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#ifdef RGBW
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sendByte(ledarray[i].w);
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#endif
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}
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wait_ns(RES);
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chSysUnlock();
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}
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