examples/ledc_check.c: Check freq and duty.

examples/peripherals/ledc/ledc_check/CMakeLists.txt

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+# The following lines of boilerplate have to be in your project's CMakeLists
+# in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.16)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(ledc)

examples/peripherals/ledc/ledc_check/main/CMakeLists.txt

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+idf_component_register(SRCS "ledc_check.c"
+                    INCLUDE_DIRS ".")

examples/peripherals/ledc/ledc_check/main/ledc_check.c

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+/* LEDC (LED Controller) basic example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+#include <stdio.h>
+#include <math.h>
+#include "driver/ledc.h"
+#include "esp_err.h"
+
+#include "freertos/FreeRTOS.h"
+#include "esp_clk_tree.h"
+
+#define CHECK_SET       0 // 1
+#if CHECK_SET != 0
+Add to the esp-idf/components/esp_driver_ledc/include/driver/ledc.h
+uint32_t ledc_calculate_divisor(uint32_t src_clk_freq, int freq_hz, uint32_t precision);
+#endif
+
+#define CHECK_ALL       0 // 1
+#define FDIV            1 // 2 // 5
+#define DELAY_ms        500 // 3000
+
+#undef ESP_ERROR_CHECK
+#define ESP_ERROR_CHECK(err) do {if (err != ESP_OK) {printf("freq=%lu, err=%d, LINE=%d\n", freq, err, __LINE__);} } while (0);
+
+#define LEDC_OUTPUT_IO          (26) // Define the output GPIO
+#define LEDC_TIMER              LEDC_TIMER_0
+#define LEDC_MODE               LEDC_HIGH_SPEED_MODE // LEDC_LOW_SPEED_MODE //
+#define LEDC_CHANNEL            LEDC_CHANNEL_0
+
+#define LEDC_DUTY               ((1UL << timer.duty_resolution) / 2) // 50%
+/* Warning:
+ * For ESP32, ESP32S2, ESP32S3, ESP32C3, ESP32C2, ESP32C6, ESP32H2, ESP32P4 targets,
+ * when LEDC_DUTY_RES selects the maximum duty resolution (i.e. value equal to SOC_LEDC_TIMER_BIT_WIDTH),
+ * 100% duty cycle is not reachable (duty cannot be set to (2 ** SOC_LEDC_TIMER_BIT_WIDTH)).
+ */
+
+#define FREQ_PERCENT            (10)
+#define DUTY_PERCENT            (10)
+
+ledc_timer_config_t timer;
+ledc_channel_config_t channel;
+
+static void check(uint32_t freq)
+{
+    printf("freq=%lu \t", freq);
+
+    // Set the LEDC peripheral configuration
+    uint32_t src_clk_freq;
+    ESP_ERROR_CHECK(esp_clk_tree_src_get_freq_hz(LEDC_USE_APB_CLK, ESP_CLK_TREE_SRC_FREQ_PRECISION_EXACT, &src_clk_freq));
+    // Prepare and then apply the LEDC PWM timer configuration
+    timer = (ledc_timer_config_t){
+        .speed_mode       = LEDC_MODE,
+        .timer_num        = LEDC_TIMER,
+        .duty_resolution  = ledc_find_suitable_duty_resolution(src_clk_freq, freq),
+        .freq_hz          = freq,
+        .clk_cfg          = LEDC_USE_APB_CLK
+    };
+    ESP_ERROR_CHECK(ledc_timer_config(&timer));
+
+    // Prepare and then apply the LEDC PWM channel configuration
+    channel = (ledc_channel_config_t){
+        .speed_mode     = LEDC_MODE,
+        .channel        = LEDC_CHANNEL,
+        .timer_sel      = LEDC_TIMER,
+        .intr_type      = LEDC_INTR_DISABLE,
+        .gpio_num       = LEDC_OUTPUT_IO,
+        .duty           = LEDC_DUTY,
+        .hpoint         = 0
+    };
+    ESP_ERROR_CHECK(ledc_channel_config(&channel));
+
+    #if CHECK_SET
+    uint32_t divider = ledc_calculate_divisor(src_clk_freq, timer.freq_hz, 0x1 << timer.duty_resolution);
+    ESP_ERROR_CHECK(ledc_timer_set(timer.speed_mode, timer.timer_num, divider, timer.duty_resolution, timer.clk_cfg));
+
+    // Set duty
+    ESP_ERROR_CHECK(ledc_set_duty(LEDC_MODE, LEDC_CHANNEL, LEDC_DUTY));
+    // Update duty to apply the new value
+    ESP_ERROR_CHECK(ledc_update_duty(LEDC_MODE, LEDC_CHANNEL));
+    #endif
+
+    vTaskDelay((2000 / freq) / portTICK_PERIOD_MS);
+
+    uint32_t get_freq = ledc_get_freq(LEDC_MODE, LEDC_CHANNEL);
+    float freq_percent = 100.0 * fabs((float)timer.freq_hz - get_freq) / timer.freq_hz;
+    uint32_t get_duty = ledc_get_duty(LEDC_MODE, LEDC_CHANNEL);
+    float duty_percent = 100.0 * fabs((float)channel.duty - get_duty) / channel.duty;
+
+    //if ((timer.freq_hz != get_freq) || (channel.duty != get_duty)) {
+    if ((freq_percent >= FREQ_PERCENT) || (duty_percent >= DUTY_PERCENT)) {
+        printf("%6.2f%% timer.freq_hz=%lu, get_freq=%lu, \t\t %6.2f%% channel.duty=%lu, get_duty=%lu \t\t timer.duty_resolution=%u\n",
+            freq_percent, timer.freq_hz, get_freq,
+            duty_percent, channel.duty, get_duty,
+            timer.duty_resolution);
+    } else {
+        printf("\n");
+    }
+}
+
+void app_main(void) {
+    uint32_t freq;
+    for(freq=1; freq<=40000000; freq+=1) {
+        #if CHECK_ALL != 1
+        if (freq > 10000000)
+            freq += 10000000 / FDIV - 1;
+        else if (freq > 1000000)
+            freq += 1000000 / FDIV - 1;
+        else if (freq > 100000)
+            freq += 100000 / FDIV - 1;
+        else if (freq > 10000)
+            freq += 10000 / FDIV - 1;
+        else if (freq > 1000)
+            freq += 1000 / FDIV - 1;
+        else if (freq > 100)
+            freq += 100 / FDIV - 1;
+        else if (freq > 10)
+            freq += 10 / FDIV - 1;
+        #endif
+
+        check(freq);
+
+        vTaskDelay(DELAY_ms / portTICK_PERIOD_MS);
+    }
+    printf("END.\n");
+}