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