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// Copyright 2019 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <stdlib.h>
#include <string.h>
#include <sys/cdefs.h>
#include "esp_log.h"
#include "esp_attr.h"
#include "led_strip.h"
#include "driver/rmt.h"
static const char *TAG = "ws2812";
#define STRIP_CHECK(a, str, goto_tag, ret_value, ...) \
do \
{ \
if (!(a)) \
{ \
ESP_LOGE(TAG, "%s(%d): " str, __FUNCTION__, __LINE__, ##__VA_ARGS__); \
ret = ret_value; \
goto goto_tag; \
} \
} while (0)
#define WS2812_T0H_NS (350)
#define WS2812_T0L_NS (1000)
#define WS2812_T1H_NS (1000)
#define WS2812_T1L_NS (350)
#define WS2812_RESET_US (280)
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;
typedef struct {
led_strip_t parent;
rmt_channel_t rmt_channel;
uint32_t strip_len;
uint8_t buffer[0];
} ws2812_t;
/**
* @brief Conver RGB data to RMT format.
*
* @note For WS2812, R,G,B each contains 256 different choices (i.e. uint8_t)
*
* @param[in] src: source data, to converted to RMT format
* @param[in] dest: place where to store the convert result
* @param[in] src_size: size of source data
* @param[in] wanted_num: number of RMT items that want to get
* @param[out] translated_size: number of source data that got converted
* @param[out] item_num: number of RMT items which are converted from source data
*/
static void IRAM_ATTR ws2812_rmt_adapter(const void *src, rmt_item32_t *dest, size_t src_size,
size_t wanted_num, size_t *translated_size, size_t *item_num)
{
if (src == NULL || dest == NULL) {
*translated_size = 0;
*item_num = 0;
return;
}
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
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++;
}
size++;
psrc++;
}
*translated_size = size;
*item_num = num;
}
static esp_err_t ws2812_set_pixel(led_strip_t *strip, uint32_t index, uint32_t red, uint32_t green, uint32_t blue)
{
esp_err_t ret = ESP_OK;
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
ws2812->buffer[start + 0] = green & 0xFF;
ws2812->buffer[start + 1] = red & 0xFF;
ws2812->buffer[start + 2] = blue & 0xFF;
return ESP_OK;
err:
return ret;
}
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,
"transmit RMT samples failed", err, ESP_FAIL);
return rmt_wait_tx_done(ws2812->rmt_channel, pdMS_TO_TICKS(timeout_ms));
err:
return ret;
}
static esp_err_t ws2812_clear(led_strip_t *strip, uint32_t timeout_ms)
{
ws2812_t *ws2812 = __containerof(strip, ws2812_t, parent);
// Write zero to turn off all leds
memset(ws2812->buffer, 0, ws2812->strip_len * 3);
return ws2812_refresh(strip, timeout_ms);
}
static esp_err_t ws2812_del(led_strip_t *strip)
{
ws2812_t *ws2812 = __containerof(strip, ws2812_t, parent);
free(ws2812);
return ESP_OK;
}
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;
ws2812_t *ws2812 = calloc(1, ws2812_size);
STRIP_CHECK(ws2812, "request memory for ws2812 failed", err, NULL);
uint32_t counter_clk_hz = 0;
STRIP_CHECK(rmt_get_counter_clock((rmt_channel_t)config->dev, &counter_clk_hz) == ESP_OK,
"get rmt counter clock failed", err, NULL);
// ns -> ticks
float ratio = (float)counter_clk_hz / 1e9;
ws2812_t0h_ticks = (uint32_t)(ratio * WS2812_T0H_NS);
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);
// set ws2812 to rmt adapter
rmt_translator_init((rmt_channel_t)config->dev, ws2812_rmt_adapter);
ws2812->rmt_channel = (rmt_channel_t)config->dev;
ws2812->strip_len = config->max_leds;
ws2812->parent.set_pixel = ws2812_set_pixel;
ws2812->parent.refresh = ws2812_refresh;
ws2812->parent.clear = ws2812_clear;
ws2812->parent.del = ws2812_del;
return &ws2812->parent;
err:
return ret;
}
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