172 lines
6.1 KiB
C
172 lines
6.1 KiB
C
// Copyright 2019 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include <stdlib.h>
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#include <string.h>
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#include <sys/cdefs.h>
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#include "esp_log.h"
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#include "esp_attr.h"
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#include "led_strip.h"
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#include "driver/rmt.h"
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static const char *TAG = "ws2812";
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#define STRIP_CHECK(a, str, goto_tag, ret_value, ...) \
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do \
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{ \
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if (!(a)) \
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{ \
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ESP_LOGE(TAG, "%s(%d): " str, __FUNCTION__, __LINE__, ##__VA_ARGS__); \
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ret = ret_value; \
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goto goto_tag; \
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} \
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} while (0)
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#define WS2812_T0H_NS (350)
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#define WS2812_T0L_NS (1000)
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#define WS2812_T1H_NS (1000)
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#define WS2812_T1L_NS (350)
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#define WS2812_RESET_US (280)
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static uint32_t ws2812_t0h_ticks = 0;
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static uint32_t ws2812_t1h_ticks = 0;
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static uint32_t ws2812_t0l_ticks = 0;
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static uint32_t ws2812_t1l_ticks = 0;
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typedef struct {
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led_strip_t parent;
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rmt_channel_t rmt_channel;
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uint32_t strip_len;
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uint8_t buffer[0];
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} ws2812_t;
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/**
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* @brief Convert RGB data to RMT format.
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*
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* @note For WS2812, R,G,B each contains 256 different choices (i.e. uint8_t)
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*
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* @param[in] src: source data, to converted to RMT format
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* @param[in] dest: place where to store the convert result
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* @param[in] src_size: size of source data
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* @param[in] wanted_num: number of RMT items that want to get
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* @param[out] translated_size: number of source data that got converted
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* @param[out] item_num: number of RMT items which are converted from source data
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*/
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static void IRAM_ATTR ws2812_rmt_adapter(const void *src, rmt_item32_t *dest, size_t src_size,
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size_t wanted_num, size_t *translated_size, size_t *item_num)
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{
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if (src == NULL || dest == NULL) {
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*translated_size = 0;
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*item_num = 0;
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return;
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}
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const rmt_item32_t bit0 = {{{ ws2812_t0h_ticks, 1, ws2812_t0l_ticks, 0 }}}; //Logical 0
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const rmt_item32_t bit1 = {{{ ws2812_t1h_ticks, 1, ws2812_t1l_ticks, 0 }}}; //Logical 1
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size_t size = 0;
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size_t num = 0;
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uint8_t *psrc = (uint8_t *)src;
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rmt_item32_t *pdest = dest;
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while (size < src_size && num < wanted_num) {
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for (int i = 0; i < 8; i++) {
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// MSB first
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if (*psrc & (1 << (7 - i))) {
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pdest->val = bit1.val;
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} else {
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pdest->val = bit0.val;
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}
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num++;
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pdest++;
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}
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size++;
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psrc++;
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}
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*translated_size = size;
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*item_num = num;
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}
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static esp_err_t ws2812_set_pixel(led_strip_t *strip, uint32_t index, uint32_t red, uint32_t green, uint32_t blue)
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{
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esp_err_t ret = ESP_OK;
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ws2812_t *ws2812 = __containerof(strip, ws2812_t, parent);
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STRIP_CHECK(index < ws2812->strip_len, "index out of the maximum number of leds", err, ESP_ERR_INVALID_ARG);
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uint32_t start = index * 3;
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// In thr order of GRB
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ws2812->buffer[start + 0] = green & 0xFF;
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ws2812->buffer[start + 1] = red & 0xFF;
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ws2812->buffer[start + 2] = blue & 0xFF;
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return ESP_OK;
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err:
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return ret;
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}
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static esp_err_t ws2812_refresh(led_strip_t *strip, uint32_t timeout_ms)
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{
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esp_err_t ret = ESP_OK;
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ws2812_t *ws2812 = __containerof(strip, ws2812_t, parent);
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STRIP_CHECK(rmt_write_sample(ws2812->rmt_channel, ws2812->buffer, ws2812->strip_len * 3, true) == ESP_OK,
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"transmit RMT samples failed", err, ESP_FAIL);
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return rmt_wait_tx_done(ws2812->rmt_channel, pdMS_TO_TICKS(timeout_ms));
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err:
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return ret;
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}
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static esp_err_t ws2812_clear(led_strip_t *strip, uint32_t timeout_ms)
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{
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ws2812_t *ws2812 = __containerof(strip, ws2812_t, parent);
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// Write zero to turn off all leds
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memset(ws2812->buffer, 0, ws2812->strip_len * 3);
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return ws2812_refresh(strip, timeout_ms);
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}
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static esp_err_t ws2812_del(led_strip_t *strip)
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{
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ws2812_t *ws2812 = __containerof(strip, ws2812_t, parent);
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free(ws2812);
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return ESP_OK;
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}
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led_strip_t *led_strip_new_rmt_ws2812(const led_strip_config_t *config)
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{
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led_strip_t *ret = NULL;
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STRIP_CHECK(config, "configuration can't be null", err, NULL);
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// 24 bits per led
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uint32_t ws2812_size = sizeof(ws2812_t) + config->max_leds * 3;
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ws2812_t *ws2812 = calloc(1, ws2812_size);
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STRIP_CHECK(ws2812, "request memory for ws2812 failed", err, NULL);
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uint32_t counter_clk_hz = 0;
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STRIP_CHECK(rmt_get_counter_clock((rmt_channel_t)config->dev, &counter_clk_hz) == ESP_OK,
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"get rmt counter clock failed", err, NULL);
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// ns -> ticks
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float ratio = (float)counter_clk_hz / 1e9;
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ws2812_t0h_ticks = (uint32_t)(ratio * WS2812_T0H_NS);
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ws2812_t0l_ticks = (uint32_t)(ratio * WS2812_T0L_NS);
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ws2812_t1h_ticks = (uint32_t)(ratio * WS2812_T1H_NS);
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ws2812_t1l_ticks = (uint32_t)(ratio * WS2812_T1L_NS);
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// set ws2812 to rmt adapter
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rmt_translator_init((rmt_channel_t)config->dev, ws2812_rmt_adapter);
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ws2812->rmt_channel = (rmt_channel_t)config->dev;
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ws2812->strip_len = config->max_leds;
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ws2812->parent.set_pixel = ws2812_set_pixel;
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ws2812->parent.refresh = ws2812_refresh;
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ws2812->parent.clear = ws2812_clear;
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ws2812->parent.del = ws2812_del;
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return &ws2812->parent;
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err:
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return ret;
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}
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