diff options
Diffstat (limited to 'drivers/arm/ws2812.c')
| -rw-r--r-- | drivers/arm/ws2812.c | 101 |
1 files changed, 100 insertions, 1 deletions
diff --git a/drivers/arm/ws2812.c b/drivers/arm/ws2812.c index 2094e50098..b076eff330 100644 --- a/drivers/arm/ws2812.c +++ b/drivers/arm/ws2812.c @@ -1 +1,100 @@ -#error("NOT SUPPORTED")
\ No newline at end of file +#include "quantum.h" +#include "ws2812.h" +#include "ch.h" +#include "hal.h" + +/* Adapted from https://github.com/bigjosh/SimpleNeoPixelDemo/ */ + +#ifndef NOP_FUDGE +# if defined(STM32F1XX) || defined(STM32F1xx) || defined(STM32F0XX) || defined(STM32F0xx) || defined(STM32F3XX) || defined(STM32F3xx) || defined(STM32L0XX) || 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); + } + + wait_ns(RES); + + chSysUnlock(); +} + +// Setleds for SK6812RGBW +void ws2812_setleds_rgbw(LED_TYPE *ledarray, uint16_t leds) { +// not supported - for now error out if its enabled +#ifdef RGBW +# error "RGBW not supported" +#endif +} |