kopia lustrzana https://github.com/espressif/esp-idf
132 wiersze
4.8 KiB
C
132 wiersze
4.8 KiB
C
/* Wave Generator Example
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This example code is in the Public Domain (or CC0 licensed, at your option.)
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DAC output channel, waveform, wave frequency can be customized in menuconfig.
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If any questions about this example or more information is needed, please read README.md before your start.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <assert.h>
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#include "freertos/queue.h"
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#include "driver/gpio.h"
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#include "driver/dac.h"
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#include "driver/gptimer.h"
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#include "esp_log.h"
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/* The timer ISR has an execution time of 5.5 micro-seconds(us).
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Therefore, a timer period less than 5.5 us will cause trigger the interrupt watchdog.
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7 us is a safe interval that will not trigger the watchdog. No need to customize it.
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*/
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#define TIMER_INTR_US 7 // Execution time of each ISR interval in micro-seconds
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#define POINT_ARR_LEN 200 // Length of points array
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#define AMP_DAC 255 // Amplitude of DAC voltage. If it's more than 256 will causes dac_output_voltage() output 0.
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#define VDD 3300 // VDD is 3.3V, 3300mV
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#define CONST_PERIOD_2_PI 6.2832
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#define DAC_CHAN CONFIG_EXAMPLE_DAC_CHANNEL // DAC_CHANNEL_1 (GPIO25) by default
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#define FREQ CONFIG_EXAMPLE_WAVE_FREQUENCY // 3kHz by default
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#define OUTPUT_POINT_NUM (int)(1000000 / (TIMER_INTR_US * FREQ) + 0.5) // The number of output wave points.
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_Static_assert(OUTPUT_POINT_NUM <= POINT_ARR_LEN, "The CONFIG_EXAMPLE_WAVE_FREQUENCY is too low and using too long buffer.");
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static int raw_val[POINT_ARR_LEN]; // Used to store raw values
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static int volt_val[POINT_ARR_LEN]; // Used to store voltage values(in mV)
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static const char *TAG = "wave_gen";
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static int g_index = 0;
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/* Timer interrupt service routine */
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static bool IRAM_ATTR on_timer_alarm_cb(gptimer_handle_t timer, const gptimer_alarm_event_data_t *edata, void *user_data)
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{
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int *head = (int *)user_data;
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/* DAC output ISR has an execution time of 4.4 us*/
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if (g_index >= OUTPUT_POINT_NUM) {
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g_index = 0;
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}
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dac_output_voltage(DAC_CHAN, *(head + g_index));
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g_index++;
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return false;
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}
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static void prepare_data(int pnt_num)
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{
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for (int i = 0; i < pnt_num; i ++) {
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#ifdef CONFIG_EXAMPLE_WAVEFORM_SINE
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raw_val[i] = (int)((sin( i * CONST_PERIOD_2_PI / pnt_num) + 1) * (double)(AMP_DAC) / 2 + 0.5);
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#elif CONFIG_EXAMPLE_WAVEFORM_TRIANGLE
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raw_val[i] = (i > (pnt_num / 2)) ? (2 * AMP_DAC * (pnt_num - i) / pnt_num) : (2 * AMP_DAC * i / pnt_num);
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#elif CONFIG_EXAMPLE_WAVEFORM_SAWTOOTH
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raw_val[i] = (i == pnt_num) ? 0 : (i * AMP_DAC / pnt_num);
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#elif CONFIG_EXAMPLE_WAVEFORM_SQUARE
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raw_val[i] = (i < (pnt_num / 2)) ? AMP_DAC : 0;
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#endif
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volt_val[i] = (int)(VDD * raw_val[i] / (float)AMP_DAC);
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}
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}
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static void log_info(void)
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{
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ESP_LOGI(TAG, "DAC output channel: %d", DAC_CHAN);
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if (DAC_CHAN == DAC_CHANNEL_1) {
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ESP_LOGI(TAG, "GPIO:%d", GPIO_NUM_25);
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} else {
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ESP_LOGI(TAG, "GPIO:%d", GPIO_NUM_26);
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}
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#ifdef CONFIG_EXAMPLE_WAVEFORM_SINE
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ESP_LOGI(TAG, "Waveform: SINE");
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#elif CONFIG_EXAMPLE_WAVEFORM_TRIANGLE
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ESP_LOGI(TAG, "Waveform: TRIANGLE");
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#elif CONFIG_EXAMPLE_WAVEFORM_SAWTOOTH
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ESP_LOGI(TAG, "Waveform: SAWTOOTH");
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#elif CONFIG_EXAMPLE_WAVEFORM_SQUARE
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ESP_LOGI(TAG, "Waveform: SQUARE");
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#endif
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ESP_LOGI(TAG, "Frequency(Hz): %d", FREQ);
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ESP_LOGI(TAG, "Output points num: %d\n", OUTPUT_POINT_NUM);
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}
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void app_main(void)
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{
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g_index = 0;
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gptimer_handle_t gptimer = NULL;
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gptimer_config_t timer_config = {
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.clk_src = GPTIMER_CLK_SRC_DEFAULT,
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.direction = GPTIMER_COUNT_UP,
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.resolution_hz = 1000000, // 1MHz, 1 tick = 1us
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};
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ESP_ERROR_CHECK(gptimer_new_timer(&timer_config, &gptimer));
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ESP_ERROR_CHECK(dac_output_enable(DAC_CHAN));
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log_info();
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prepare_data(OUTPUT_POINT_NUM);
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gptimer_alarm_config_t alarm_config = {
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.reload_count = 0,
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.alarm_count = TIMER_INTR_US,
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.flags.auto_reload_on_alarm = true,
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};
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gptimer_event_callbacks_t cbs = {
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.on_alarm = on_timer_alarm_cb,
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};
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ESP_ERROR_CHECK(gptimer_register_event_callbacks(gptimer, &cbs, raw_val));
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ESP_ERROR_CHECK(gptimer_set_alarm_action(gptimer, &alarm_config));
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ESP_ERROR_CHECK(gptimer_enable(gptimer));
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ESP_ERROR_CHECK(gptimer_start(gptimer));
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while (1) {
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vTaskDelay(10);
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#if CONFIG_EXAMPLE_LOG_VOLTAGE
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if (g_index < OUTPUT_POINT_NUM) {
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ESP_LOGI(TAG, "Output voltage(mV): %d", volt_val[g_index]);
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ESP_LOGD(TAG, "g_index: %d\n", g_index);
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}
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#endif
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}
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}
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