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ws2812 fixes #610

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ws2812 fixes #610

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04f21fd
ws2812: fix rgbw
balika011 Feb 18, 2025
e40cdf6
ws2812: 400KHz support
balika011 Feb 18, 2025
ea5719e
ws2812: clean up and fix typo
balika011 Feb 18, 2025
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35 changes: 30 additions & 5 deletions pio/ws2812/ws2812.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,15 +17,19 @@
* Take into consideration if your WS2812 is a RGB or RGBW variant.
*
* If it is RGBW, you need to set IS_RGBW to true and provide 4 bytes per
* pixel (Red, Green, Blue, White) and use urgbw_u32().
* pixel (Red, Green, Blue, White) and use urgb_u32() or urgbw_u32().
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I can't tell why you've effectively removed support for urgbw_u32() ?

*
* If it is RGB, set IS_RGBW to false and provide 3 bytes per pixel (Red,
* Green, Blue) and use urgb_u32().
*
* When RGBW is used with urgb_u32(), the White channel will be ignored (off).
*
* Some strips only support 400Khz.
*
* Set IS_800KHz to false if your strip is like that.
*/
#define IS_RGBW false
#define IS_800KHz true
#define NUM_PIXELS 150

#ifdef PICO_DEFAULT_WS2812_PIN
Expand All @@ -40,6 +44,7 @@
#error Attempting to use a pin>=32 on a platform that does not support it
#endif

#ifndef IS_RGBW
static inline void put_pixel(PIO pio, uint sm, uint32_t pixel_grb) {
pio_sm_put_blocking(pio, sm, pixel_grb << 8u);
}
Expand All @@ -50,14 +55,32 @@ static inline uint32_t urgb_u32(uint8_t r, uint8_t g, uint8_t b) {
((uint32_t) (g) << 16) |
(uint32_t) (b);
}
#else
static inline void put_pixel(PIO pio, uint sm, uint32_t pixel_grb) {
pio_sm_put_blocking(pio, sm, pixel_grb);
}

static inline uint32_t urgbw_u32(uint8_t r, uint8_t g, uint8_t b, uint8_t w) {
static inline uint32_t urgb_u32(uint8_t r, uint8_t g, uint8_t b) {
return
((uint32_t) (r) << 8) |
((uint32_t) (g) << 16) |
(uint32_t) (b);
}

/*
* NOTE:
* This code here is unused in this example, however can be useful if you want to set the white brightness too.
* Keeping it here for later reference.
* You may remove __attribute__((unused)) in case you use it.
*/
static inline uint32_t __attribute__((unused)) urgbw_u32(uint8_t r, uint8_t g, uint8_t b, uint8_t w) {
return
((uint32_t) (r) << 8) |
((uint32_t) (g) << 16) |
((uint32_t) (w) << 24) |
(uint32_t) (b);
}
#endif

void pattern_snakes(PIO pio, uint sm, uint len, uint t) {
for (uint i = 0; i < len; ++i) {
Expand Down Expand Up @@ -91,7 +114,7 @@ void pattern_greys(PIO pio, uint sm, uint len, uint t) {
uint max = 100; // let's not draw too much current!
t %= max;
for (uint i = 0; i < len; ++i) {
put_pixel(pio, sm, t * 0x10101);
put_pixel(pio, sm, t * 0x1010101);
if (++t >= max) t = 0;
}
}
Expand All @@ -108,11 +131,9 @@ const struct {
};

int main() {
//set_sys_clock_48();
stdio_init_all();
printf("WS2812 Smoke Test, using pin %d\n", WS2812_PIN);

// todo get free sm
PIO pio;
uint sm;
uint offset;
Expand All @@ -123,7 +144,11 @@ int main() {
bool success = pio_claim_free_sm_and_add_program_for_gpio_range(&ws2812_program, &pio, &sm, &offset, WS2812_PIN, 1, true);
hard_assert(success);

#if IS_800KHz
ws2812_program_init(pio, sm, offset, WS2812_PIN, 800000, IS_RGBW);
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Perhaps it makes more sense to add e.g. #define WS2812_FREQUENCY 800000 and then pass that to ws2812_program_init, rather than adding a #if IS_800KHz section?

#else
ws2812_program_init(pio, sm, offset, WS2812_PIN, 400000, IS_RGBW);
#endif

int t = 0;
while (1) {
Expand Down