122 lines
5.0 KiB
C
122 lines
5.0 KiB
C
/*
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* SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: CC0-1.0
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*/
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#include <inttypes.h>
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#include <math.h>
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#include "soc/dac_channel.h"
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#include "esp_adc/adc_oneshot.h"
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#include "esp_check.h"
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#include "dac_continuous_example.h"
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/**
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* 有两种方式可以连续将数字数据转换为模拟信号：
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* - 使用定时器：在定时器中断中定期设置DAC电压
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* 这种方式，DAC可以达到相对较低的转换频率
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* 但与使用DMA相比，这不是一种高效的方式
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* - 使用DMA：通过DMA传输数据缓冲区，
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* 转换频率由DMA传输速度控制
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* 这种方式，转换频率可以达到几MHz，
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* 但由于受DMA时钟源限制，无法达到很低的转换频率
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* 一般来说，推荐使用DMA，如果DMA外设被占用或所需的转换频率很低，
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* 则使用定时器代替
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*/
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/* ADC配置 */
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#if CONFIG_IDF_TARGET_ESP32
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#define EXAMPLE_DAC_CHAN0_ADC_CHAN ADC_CHANNEL_8 // GPIO25，与DAC通道0相同
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#define EXAMPLE_DAC_CHAN1_ADC_CHAN ADC_CHANNEL_9 // GPIO26，与DAC通道1相同
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#define EXAMPLE_ADC_WIDTH ADC_WIDTH_BIT_12
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#elif CONFIG_IDF_TARGET_ESP32S2
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#define EXAMPLE_DAC_CHAN0_ADC_CHAN ADC_CHANNEL_6 // GPIO17，与DAC通道0相同
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#define EXAMPLE_DAC_CHAN1_ADC_CHAN ADC_CHANNEL_7 // GPIO18，与DAC通道1相同
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#define EXAMPLE_ADC_WIDTH ADC_WIDTH_BIT_13
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#endif
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#define EXAMPLE_DAC_CHAN0_IO DAC_CHAN0_GPIO_NUM // DAC通道0的IO号
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#define EXAMPLE_DAC_CHAN1_IO DAC_CHAN1_GPIO_NUM // DAC通道1的IO号
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#define EXAMPLE_ADC_ATTEN ADC_ATTEN_DB_12
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_Static_assert(EXAMPLE_DAC_AMPLITUDE < 256, "DAC精度为8位，不支持超过255的幅度");
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static const char *TAG = "dac continuous";
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uint8_t sin_wav[EXAMPLE_ARRAY_LEN]; // 用于存储正弦波值
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uint8_t tri_wav[EXAMPLE_ARRAY_LEN]; // 用于存储三角波值
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uint8_t saw_wav[EXAMPLE_ARRAY_LEN]; // 用于存储锯齿波值
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uint8_t squ_wav[EXAMPLE_ARRAY_LEN]; // 用于存储方波值
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static void example_generate_wave(void)
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{
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uint32_t pnt_num = EXAMPLE_ARRAY_LEN;
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for (int i = 0; i < pnt_num; i ++) {
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sin_wav[i] = (uint8_t)((sin(i * CONST_PERIOD_2_PI / pnt_num) + 1) * (double)(EXAMPLE_DAC_AMPLITUDE) / 2 + 0.5);
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tri_wav[i] = (i > (pnt_num / 2)) ? (2 * EXAMPLE_DAC_AMPLITUDE * (pnt_num - i) / pnt_num) : (2 * EXAMPLE_DAC_AMPLITUDE * i / pnt_num);
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saw_wav[i] = (i == pnt_num) ? 0 : (i * EXAMPLE_DAC_AMPLITUDE / pnt_num);
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squ_wav[i] = (i < (pnt_num / 2)) ? EXAMPLE_DAC_AMPLITUDE : 0;
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}
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}
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void example_log_info(uint32_t conv_freq, uint32_t wave_freq)
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{
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ESP_LOGI(TAG, "--------------------------------------------------");
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#if CONFIG_EXAMPLE_DAC_CONTINUOUS_BY_DMA
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ESP_LOGI(TAG, "DAC continuous output by DMA");
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#else
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ESP_LOGI(TAG, "DAC continuous output by timer");
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#endif
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ESP_LOGI(TAG, "DAC channel 0 io: GPIO_NUM_%d", EXAMPLE_DAC_CHAN0_IO);
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ESP_LOGI(TAG, "DAC channel 1 io: GPIO_NUM_%d", EXAMPLE_DAC_CHAN1_IO);
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ESP_LOGI(TAG, "Waveform: SINE -> TRIANGLE -> SAWTOOTH -> SQUARE");
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ESP_LOGI(TAG, "DAC conversion frequency (Hz): %"PRIu32, conv_freq);
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ESP_LOGI(TAG, "DAC wave frequency (Hz): %"PRIu32, wave_freq);
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ESP_LOGI(TAG, "--------------------------------------------------");
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}
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static void adc_monitor_task(void *args)
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{
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adc_oneshot_unit_handle_t adc2_handle = (adc_oneshot_unit_handle_t)args;
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int chan0_val = 0;
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int chan1_val = 0;
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while (1) {
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/* 读取DAC输出电压 */
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ESP_ERROR_CHECK(adc_oneshot_read(adc2_handle, EXAMPLE_DAC_CHAN0_ADC_CHAN, &chan0_val));
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ESP_ERROR_CHECK(adc_oneshot_read(adc2_handle, EXAMPLE_DAC_CHAN1_ADC_CHAN, &chan1_val));
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printf("DAC channel 0 value: %4d\tDAC channel 1 value: %4d\n", chan0_val, chan1_val);
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vTaskDelay(pdMS_TO_TICKS(100));
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}
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}
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void app_main(void)
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{
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example_generate_wave();
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#if CONFIG_EXAMPLE_DAC_CONTINUOUS_BY_DMA
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/* 使用DMA输出2kHz波形 */
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example_dac_continuous_by_dma();
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#else
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/* 使用定时器中断输出50Hz波形 */
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example_dac_continuous_by_timer();
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#endif
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/* 设置ADC2通道，这些通道内部连接到DAC通道 */
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adc_oneshot_unit_handle_t adc2_handle;
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adc_oneshot_unit_init_cfg_t adc_cfg = {
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.unit_id = ADC_UNIT_2,
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.ulp_mode = false,
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};
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ESP_ERROR_CHECK(adc_oneshot_new_unit(&adc_cfg, &adc2_handle));
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adc_oneshot_chan_cfg_t chan_cfg = {
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.atten = EXAMPLE_ADC_ATTEN,
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.bitwidth = ADC_BITWIDTH_DEFAULT,
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};
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ESP_ERROR_CHECK(adc_oneshot_config_channel(adc2_handle, EXAMPLE_DAC_CHAN0_ADC_CHAN, &chan_cfg));
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ESP_ERROR_CHECK(adc_oneshot_config_channel(adc2_handle, EXAMPLE_DAC_CHAN1_ADC_CHAN, &chan_cfg));
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/* 创建ADC监控任务以检测DAC引脚上的电压 */
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xTaskCreate(adc_monitor_task, "adc_monitor_task", 4096, adc2_handle, 5, NULL);
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}
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