diff options
author | Nick Brassel <nick@tzarc.org> | 2021-08-29 08:20:25 +1000 |
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committer | Nick Brassel <nick@tzarc.org> | 2021-08-29 08:20:25 +1000 |
commit | f061ca497464fe85284906fb163a33eaee7a91ef (patch) | |
tree | 33ef1bfb529aed382e8526c607c4e18717f92571 /platforms/chibios/drivers/ws2812.c | |
parent | ff65185dec6f97be1eb49f17cea526a0d0bbf3d6 (diff) | |
parent | 4bad375d7c09d949a9dcdd4feba147c9c7a67ec6 (diff) |
Breaking changes develop merge to master, 2021Q3 edition. (#14196)
Diffstat (limited to 'platforms/chibios/drivers/ws2812.c')
-rw-r--r-- | platforms/chibios/drivers/ws2812.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/platforms/chibios/drivers/ws2812.c b/platforms/chibios/drivers/ws2812.c new file mode 100644 index 0000000000..0d12e2fb79 --- /dev/null +++ b/platforms/chibios/drivers/ws2812.c @@ -0,0 +1,114 @@ +#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 + +// Push Pull or Open Drain Configuration +// Default Push Pull +#ifndef WS2812_EXTERNAL_PULLUP +# define WS2812_OUTPUT_MODE PAL_MODE_OUTPUT_PUSHPULL +#else +# define WS2812_OUTPUT_MODE PAL_MODE_OUTPUT_OPENDRAIN +#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 (1000 * WS2812_TRST_US) // 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) { palSetLineMode(RGB_DI_PIN, WS2812_OUTPUT_MODE); } + +// 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 +#if (WS2812_BYTE_ORDER == WS2812_BYTE_ORDER_GRB) + sendByte(ledarray[i].g); + sendByte(ledarray[i].r); + sendByte(ledarray[i].b); +#elif (WS2812_BYTE_ORDER == WS2812_BYTE_ORDER_RGB) + sendByte(ledarray[i].r); + sendByte(ledarray[i].g); + sendByte(ledarray[i].b); +#elif (WS2812_BYTE_ORDER == WS2812_BYTE_ORDER_BGR) + sendByte(ledarray[i].b); + sendByte(ledarray[i].g); + sendByte(ledarray[i].r); +#endif + +#ifdef RGBW + sendByte(ledarray[i].w); +#endif + } + + wait_ns(RES); + + chSysUnlock(); +} |