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fix timing by adding the reset signal

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This commit is contained in:
Jacques Supcik 2022-04-25 00:07:35 +02:00
parent 45c1d1cba2
commit c7fe38926a
1 changed files with 31 additions and 14 deletions
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45
examples/common_components/led_strip/led_strip_rmt_ws2812.c
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@ -43,6 +43,7 @@ static uint32_t ws2812_t0h_ticks = 0;
static uint32_t ws2812_t1h_ticks = 0;
static uint32_t ws2812_t0l_ticks = 0;
static uint32_t ws2812_t1l_ticks = 0;
static uint32_t ws2812_reset_ticks = 0;
typedef struct {
led_strip_t parent;
@ -73,24 +74,39 @@ static void IRAM_ATTR ws2812_rmt_adapter(const void *src, rmt_item32_t *dest, si
}
const rmt_item32_t bit0 = {{{ ws2812_t0h_ticks, 1, ws2812_t0l_ticks, 0 }}}; //Logical 0
const rmt_item32_t bit1 = {{{ ws2812_t1h_ticks, 1, ws2812_t1l_ticks, 0 }}}; //Logical 1
const rmt_item32_t reset = {{{ ws2812_reset_ticks, 0, 0, 0 }}}; // Reset signal
const rmt_item32_t nop = {{{ 0, 0, 0, 0 }}}; // Null signal
size_t size = 0;
size_t num = 0;
uint8_t *psrc = (uint8_t *)src;
rmt_item32_t *pdest = dest;
while (size < src_size && num < wanted_num) {
for (int i = 0; i < 8; i++) {
// MSB first
if (*psrc & (1 << (7 - i))) {
pdest->val = bit1.val;
} else {
pdest->val = bit0.val;
}
num++;
pdest++;
while (size < (src_size - 1) && num < wanted_num) {
// MSB first, so we decremented `i` from 7 to 0.
// Note that `i` must be signed (e.g. `int`) for this to work!
for (int i = 7; i >= 0; i--) {
(pdest++)->val = (*psrc & (1 << i)) ? bit1.val : bit0.val;
}
num += 8;
size++;
psrc++;
}
// Send reset signal (LOW for `WS2812_RESET_US` microseconds)
// The check of the size is still needed, because `src_size` could be 0.
// (Note that the check could be replaced by `src_size > 0`,
// but it is more clear this way.)
if (size < src_size && num < wanted_num) {
(pdest++)->val = reset.val; // The first bit is the reset signal
// we just sent the first bit, so we start the loop with i = 1
for (int i = 1; i < 8; i++) { // complete the byte with 7 NOP signals
(pdest++)->val = nop.val;
}
num += 8;
size++;
// we don't need to increment `psrc`, because we no longer use it
}
*translated_size = size;
*item_num = num;
}
@ -101,7 +117,7 @@ static esp_err_t ws2812_set_pixel(led_strip_t *strip, uint32_t index, uint32_t r
ws2812_t *ws2812 = __containerof(strip, ws2812_t, parent);
STRIP_CHECK(index < ws2812->strip_len, "index out of the maximum number of leds", err, ESP_ERR_INVALID_ARG);
uint32_t start = index * 3;
// In thr order of GRB
// In the order of GRB
ws2812->buffer[start + 0] = green & 0xFF;
ws2812->buffer[start + 1] = red & 0xFF;
ws2812->buffer[start + 2] = blue & 0xFF;
@ -114,7 +130,7 @@ static esp_err_t ws2812_refresh(led_strip_t *strip, uint32_t timeout_ms)
{
esp_err_t ret = ESP_OK;
ws2812_t *ws2812 = __containerof(strip, ws2812_t, parent);
STRIP_CHECK(rmt_write_sample(ws2812->rmt_channel, ws2812->buffer, ws2812->strip_len * 3, true) == ESP_OK,
STRIP_CHECK(rmt_write_sample(ws2812->rmt_channel, ws2812->buffer, ws2812->strip_len * 3 + 1, true) == ESP_OK,
"transmit RMT samples failed", err, ESP_FAIL);
return rmt_wait_tx_done(ws2812->rmt_channel, pdMS_TO_TICKS(timeout_ms));
err:
@ -141,8 +157,8 @@ led_strip_t *led_strip_new_rmt_ws2812(const led_strip_config_t *config)
led_strip_t *ret = NULL;
STRIP_CHECK(config, "configuration can't be null", err, NULL);
// 24 bits per led
uint32_t ws2812_size = sizeof(ws2812_t) + config->max_leds * 3;
// 24 bits per led + reset
uint32_t ws2812_size = sizeof(ws2812_t) + config->max_leds * 3 + 1;
ws2812_t *ws2812 = calloc(1, ws2812_size);
STRIP_CHECK(ws2812, "request memory for ws2812 failed", err, NULL);
@ -155,6 +171,7 @@ led_strip_t *led_strip_new_rmt_ws2812(const led_strip_config_t *config)
ws2812_t0l_ticks = (uint32_t)(ratio * WS2812_T0L_NS);
ws2812_t1h_ticks = (uint32_t)(ratio * WS2812_T1H_NS);
ws2812_t1l_ticks = (uint32_t)(ratio * WS2812_T1L_NS);
ws2812_reset_ticks = (uint32_t)(ratio * WS2812_RESET_US * 1000);
// set ws2812 to rmt adapter
rmt_translator_init((rmt_channel_t)config->dev, ws2812_rmt_adapter);