Merge branch 'bugfix/ledc_consecutive_fade_v4.1' into 'release/v4.1'

ledc: Bugfixes for issues related to fade protection (backport v4.1)

See merge request espressif/esp-idf!16957

components/driver/include/driver/ledc.h

@@ -61,6 +61,7 @@ esp_err_t ledc_timer_config(const ledc_timer_config_t* timer_conf);
  * @brief LEDC update channel parameters
  * @note  Call this function to activate the LEDC updated parameters.
  *        After ledc_set_duty, we need to call this function to update the settings.
+ *        And the new LEDC parameters don't take effect until the next PWM cycle.
  * @note  ledc_set_duty, ledc_set_duty_with_hpoint and ledc_update_duty are not thread-safe, do not call these functions to
  *        control one LEDC channel in different tasks at the same time.
  *        A thread-safe version of API is ledc_set_duty_and_update
@@ -178,6 +179,9 @@ esp_err_t ledc_set_duty(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t
 
 /**
  * @brief LEDC get duty
+ *        This function returns the duty at the present PWM cycle.
+ *        You shouldn't expect the function to return the new duty in the same cycle of calling ledc_update_duty,
+ *        because duty update doesn't take effect until the next cycle.
  *
  * @param speed_mode Select the LEDC speed_mode, high-speed mode and low-speed mode
  * @param channel LEDC channel (0-7), select from ledc_channel_t
@@ -360,7 +364,8 @@ void ledc_fade_func_uninstall(void);
  *        Other duty operations will have to wait until the fade operation has finished.
  * @param speed_mode Select the LEDC speed_mode, high-speed mode and low-speed mode
  * @param channel LEDC channel number
- * @param fade_mode Whether to block until fading done.
+ * @param fade_mode Whether to block until fading done. See ledc_types.h ledc_fade_mode_t for more info.
+ *        Note that this function will not return until fading to the target duty if LEDC_FADE_WAIT_DONE mode is selected.
  *
  * @return
  *     - ESP_OK Success

components/driver/ledc.c

@@ -199,7 +199,7 @@ esp_err_t ledc_timer_set(ledc_mode_t speed_mode, ledc_timer_t timer_sel, uint32_
 static IRAM_ATTR esp_err_t ledc_duty_config(ledc_mode_t speed_mode, ledc_channel_t channel, int hpoint_val, int duty_val,
     ledc_duty_direction_t duty_direction, uint32_t duty_num, uint32_t duty_cycle, uint32_t duty_scale)
 {
-    portENTER_CRITICAL(&ledc_spinlock);
+    portENTER_CRITICAL_SAFE(&ledc_spinlock);
     if (hpoint_val >= 0) {
         ledc_hal_set_hpoint(&(p_ledc_obj[speed_mode]->ledc_hal), channel, hpoint_val);
     }
@@ -211,7 +211,7 @@ static IRAM_ATTR esp_err_t ledc_duty_config(ledc_mode_t speed_mode, ledc_channel
     ledc_hal_set_duty_cycle(&(p_ledc_obj[speed_mode]->ledc_hal), channel, duty_cycle);
     ledc_hal_set_duty_scale(&(p_ledc_obj[speed_mode]->ledc_hal), channel, duty_scale);
     ledc_ls_channel_update(speed_mode, channel);
-    portEXIT_CRITICAL(&ledc_spinlock);
+    portEXIT_CRITICAL_SAFE(&ledc_spinlock);
     return ESP_OK;
 }
 
@@ -284,7 +284,7 @@ static esp_err_t ledc_set_timer_div(ledc_mode_t speed_mode, ledc_timer_t timer_n
     if ((speed_mode == LEDC_LOW_SPEED_MODE) && (clk_cfg == LEDC_USE_RTC8M_CLK)) {
         if(s_ledc_slow_clk_8M == 0) {
             if (ledc_slow_clk_calibrate() == false) {
-                goto error;    
+                goto error;
             }
         }
         div_param = ( (uint64_t) s_ledc_slow_clk_8M << 8 ) / freq_hz / precision;
@@ -472,8 +472,8 @@ esp_err_t ledc_set_duty_with_hpoint(ledc_mode_t speed_mode, ledc_channel_t chann
                      hpoint,          //uint32_t hpoint_val,
                      duty,           //uint32_t duty_val,
                      1,               //uint32_t increase,
-                     1,               //uint32_t duty_num,
-                     1,               //uint32_t duty_cycle,
+                     0,               //uint32_t duty_num,
+                     0,               //uint32_t duty_cycle,
                      0                //uint32_t duty_scale
                      );
     _ledc_fade_hw_release(speed_mode, channel);
@@ -492,8 +492,8 @@ esp_err_t ledc_set_duty(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t
                      LEDC_VAL_NO_CHANGE,
                      duty,           //uint32_t duty_val,
                      1,               //uint32_t increase,
-                     1,               //uint32_t duty_num,
-                     1,               //uint32_t duty_cycle,
+                     0,               //uint32_t duty_num,
+                     0,               //uint32_t duty_cycle,
                      0                //uint32_t duty_scale
                      );
     _ledc_fade_hw_release(speed_mode, channel);
@@ -573,9 +573,9 @@ void IRAM_ATTR ledc_fade_isr(void* arg)
             ledc_calc_fade_end_channel(&intr_status, &channel);
 
             // clear interrupt
-            portENTER_CRITICAL(&ledc_spinlock);
+            portENTER_CRITICAL_ISR(&ledc_spinlock);
             ledc_hal_clear_fade_end_intr_status(&(p_ledc_obj[speed_mode]->ledc_hal), channel);
-            portEXIT_CRITICAL(&ledc_spinlock);
+            portEXIT_CRITICAL_ISR(&ledc_spinlock);
 
             if (s_ledc_fade_rec[speed_mode][channel] == NULL) {
                 //fade object not initialized yet.
@@ -621,9 +621,9 @@ void IRAM_ATTR ledc_fade_isr(void* arg)
                     1,
                     0);
             }
-            portENTER_CRITICAL(&ledc_spinlock);
+            portENTER_CRITICAL_ISR(&ledc_spinlock);
             ledc_hal_set_duty_start(&(p_ledc_obj[speed_mode]->ledc_hal), channel, true);
-            portEXIT_CRITICAL(&ledc_spinlock);
+            portEXIT_CRITICAL_ISR(&ledc_spinlock);
         }
     }
 }
@@ -763,7 +763,10 @@ static void _ledc_fade_start(ledc_mode_t speed_mode, ledc_channel_t channel, led
     ledc_enable_intr_type(speed_mode, channel, LEDC_INTR_FADE_END);
     ledc_update_duty(speed_mode, channel);
     if (fade_mode == LEDC_FADE_WAIT_DONE) {
-        xSemaphoreTake(s_ledc_fade_rec[speed_mode][channel]->ledc_fade_sem, portMAX_DELAY);
+        // Waiting for fade done
+        _ledc_fade_hw_acquire(speed_mode, channel);
+        // Release hardware to support next time fade configure
+        _ledc_fade_hw_release(speed_mode, channel);
     }
 }
 
@@ -805,7 +808,6 @@ esp_err_t ledc_fade_start(ledc_mode_t speed_mode, ledc_channel_t channel, ledc_f
     LEDC_CHECK(p_ledc_obj[speed_mode] != NULL, LEDC_NOT_INIT, ESP_ERR_INVALID_STATE);
     _ledc_fade_hw_acquire(speed_mode, channel);
     _ledc_fade_start(speed_mode, channel, fade_mode);
-    _ledc_fade_hw_release(speed_mode, channel);
     return ESP_OK;
 }
 
@@ -842,14 +844,13 @@ esp_err_t ledc_set_duty_and_update(ledc_mode_t speed_mode, ledc_channel_t channe
     LEDC_ARG_CHECK(speed_mode < LEDC_SPEED_MODE_MAX, "speed_mode");
     LEDC_ARG_CHECK(channel < LEDC_CHANNEL_MAX, "channel");
     LEDC_ARG_CHECK(duty <= ledc_get_max_duty(speed_mode, channel), "target_duty");
+    LEDC_ARG_CHECK(hpoint <= LEDC_HPOINT_VAL_MAX, "hpoint");
     LEDC_CHECK(p_ledc_obj[speed_mode] != NULL, LEDC_NOT_INIT, ESP_ERR_INVALID_STATE);
-    LEDC_CHECK(ledc_fade_channel_init_check(speed_mode, channel) == ESP_OK , LEDC_FADE_INIT_ERROR_STR, ESP_FAIL);
-    _ledc_op_lock_acquire(speed_mode, channel);
+    LEDC_CHECK(ledc_fade_channel_init_check(speed_mode, channel) == ESP_OK, LEDC_FADE_INIT_ERROR_STR, ESP_FAIL);
     _ledc_fade_hw_acquire(speed_mode, channel);
-    _ledc_set_fade_with_step(speed_mode, channel, duty, 0, 1);
-    _ledc_fade_start(speed_mode, channel, LEDC_FADE_WAIT_DONE);
+    ledc_duty_config(speed_mode, channel, hpoint, duty, 1, 0, 0, 0);
+    ledc_update_duty(speed_mode, channel);
     _ledc_fade_hw_release(speed_mode, channel);
-    _ledc_op_lock_release(speed_mode, channel);
     return ESP_OK;
 }
 
@@ -865,9 +866,6 @@ esp_err_t ledc_set_fade_time_and_start(ledc_mode_t speed_mode, ledc_channel_t ch
     _ledc_fade_hw_acquire(speed_mode, channel);
     _ledc_set_fade_with_time(speed_mode, channel, target_duty, max_fade_time_ms);
     _ledc_fade_start(speed_mode, channel, fade_mode);
-    if (fade_mode == LEDC_FADE_WAIT_DONE) {
-        _ledc_fade_hw_release(speed_mode, channel);
-    }
     _ledc_op_lock_release(speed_mode, channel);
     return ESP_OK;
 }
@@ -886,9 +884,6 @@ esp_err_t ledc_set_fade_step_and_start(ledc_mode_t speed_mode, ledc_channel_t ch
     _ledc_fade_hw_acquire(speed_mode, channel);
     _ledc_set_fade_with_step(speed_mode, channel, target_duty, scale, cycle_num);
     _ledc_fade_start(speed_mode, channel, fade_mode);
-    if (fade_mode == LEDC_FADE_WAIT_DONE) {
-        _ledc_fade_hw_release(speed_mode, channel);
-    }
     _ledc_op_lock_release(speed_mode, channel);
     return ESP_OK;
 }

components/driver/test/test_ledc.c

@@ -96,12 +96,39 @@ static void timer_frequency_test(ledc_channel_t channel, ledc_timer_bit_t timer_
     frequency_set_get(ledc_ch_config.speed_mode, ledc_ch_config.timer_sel, 9000, 9025, 5);
 }
 
+static void fade_setup(void)
+{
+    ledc_channel_config_t ledc_ch_config = {
+        .gpio_num = PULSE_IO,
+        .speed_mode = LEDC_HIGH_SPEED_MODE,
+        .channel = LEDC_CHANNEL_0,
+        .intr_type = LEDC_INTR_DISABLE,
+        .timer_sel = LEDC_TIMER_0,
+        .duty = 0,
+        .hpoint = 0,
+    };
+    ledc_timer_config_t ledc_time_config = {
+        .speed_mode = LEDC_HIGH_SPEED_MODE,
+        .duty_resolution = LEDC_TIMER_13_BIT,
+        .timer_num = LEDC_TIMER_0,
+        .freq_hz = 2000,
+        .clk_cfg = LEDC_USE_APB_CLK,
+    };
+
+    TEST_ESP_OK(ledc_channel_config(&ledc_ch_config));
+    TEST_ESP_OK(ledc_timer_config(&ledc_time_config));
+    vTaskDelay(5 / portTICK_PERIOD_MS);
+
+    //initialize fade service
+    TEST_ESP_OK(ledc_fade_func_install(0));
+}
+
 static void timer_duty_set_get(ledc_mode_t speed_mode, ledc_channel_t channel, uint32_t duty)
 {
     TEST_ESP_OK(ledc_set_duty(speed_mode, channel, duty));
     TEST_ESP_OK(ledc_update_duty(speed_mode, channel));
-    vTaskDelay(1000 / portTICK_RATE_MS);
-    TEST_ASSERT_EQUAL_INT32(ledc_get_duty(speed_mode, channel), duty);
+    vTaskDelay(100 / portTICK_RATE_MS);
+    TEST_ASSERT_EQUAL_INT32(duty, ledc_get_duty(speed_mode, channel));
 }
 
 // use logic analyzer to view
@@ -274,9 +301,9 @@ TEST_CASE("LEDC set and get frequency", "[ledc][test_env=UT_T1_LEDC][timeout=60]
     timer_frequency_test(LEDC_CHANNEL_0, LEDC_TIMER_13_BIT, LEDC_TIMER_3, LEDC_LOW_SPEED_MODE);
 }
 
-// the duty need to be detected by waveform given by the logic analyzer
-// can't get it directly, so set it "ignore"
-TEST_CASE("LEDC set and get dut(with logic analyzer)", "[ledc][ignore]")
+// duty should be manually checked from the waveform using a logic analyzer
+// this test is enabled only for testting the settings
+TEST_CASE("LEDC set and get duty", "[ledc]")
 {
     ledc_timer_t timer_list[4] = {LEDC_TIMER_0, LEDC_TIMER_1, LEDC_TIMER_2, LEDC_TIMER_3};
 #ifdef CONFIG_IDF_TARGET_ESP32
@@ -328,7 +355,7 @@ TEST_CASE("LEDC timer set", "[ledc][test_env=UT_T1_LEDC]")
     count = wave_count(1000);
     TEST_ASSERT_UINT32_WITHIN(10, count, freq_get);
 
-    //set timer 3 as 500Hz, use APB_CLK
+    //set timer 0 as 500Hz, use APB_CLK
     TEST_ESP_OK(ledc_timer_set(test_speed_mode, LEDC_TIMER_0, 5000, 13, LEDC_APB_CLK));
     TEST_ESP_OK(ledc_timer_rst(test_speed_mode, LEDC_TIMER_0));
     TEST_ASSERT_EQUAL_INT32(ledc_get_freq(test_speed_mode, LEDC_TIMER_0), 500);
@@ -400,102 +427,111 @@ TEST_CASE("LEDC timer pause and resume", "[ledc][test_env=UT_T1_LEDC]")
     TEST_ASSERT_UINT32_WITHIN(5, count, 5000);
 }
 
-TEST_CASE("LEDC fade with time(logic analyzer)", "[ledc][test_env=UT_T1_LEDC]")
+TEST_CASE("LEDC fade with time", "[ledc]")
 {
-#ifdef CONFIG_FREERTOS_CHECK_PORT_CRITICAL_COMPLIANCE
-    return;
-#endif
-
-#ifdef CONFIG_IDF_TARGET_ESP32
     const ledc_mode_t test_speed_mode = LEDC_HIGH_SPEED_MODE;
-#elif defined CONFIG_IDF_TARGET_ESP32S2BETA
-    const ledc_mode_t test_speed_mode = LEDC_LOW_SPEED_MODE;
-#endif
-    ledc_channel_config_t ledc_ch_config = {
-        .gpio_num = PULSE_IO,
-        .speed_mode = test_speed_mode,
-        .channel  = LEDC_CHANNEL_0,
-        .intr_type = LEDC_INTR_DISABLE,
-        .timer_sel = LEDC_TIMER_0,
-        .duty = 0,
-        .hpoint = 0,
-    };
-    TEST_ESP_OK(ledc_channel_config(&ledc_ch_config));
+    fade_setup();
 
-    ledc_timer_config_t ledc_time_config = {
-        .speed_mode = test_speed_mode,
-        .duty_resolution = LEDC_TIMER_13_BIT,
-        .timer_num = LEDC_TIMER_0,
-        .freq_hz = 5000,
-        .clk_cfg = LEDC_USE_APB_CLK,
-    };
-    TEST_ESP_OK(ledc_timer_config(&ledc_time_config));
-
-    //initialize fade service
-    TEST_ESP_OK(ledc_fade_func_install(0));
-
-    TEST_ESP_OK(ledc_set_fade_with_time(test_speed_mode, LEDC_CHANNEL_0, 4000, 1000));
+    TEST_ESP_OK(ledc_set_fade_with_time(test_speed_mode, LEDC_CHANNEL_0, 4000, 200));
     TEST_ESP_OK(ledc_fade_start(test_speed_mode, LEDC_CHANNEL_0, LEDC_FADE_WAIT_DONE));
-    vTaskDelay(1000 / portTICK_RATE_MS);
-    TEST_ASSERT_EQUAL_INT32(ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0), 4000);
+    TEST_ASSERT_EQUAL_INT32(4000, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
 
-    TEST_ESP_OK(ledc_set_fade_with_time(test_speed_mode, LEDC_CHANNEL_0, 0, 1000));
+    TEST_ESP_OK(ledc_set_fade_with_time(test_speed_mode, LEDC_CHANNEL_0, 0, 200));
     TEST_ESP_OK(ledc_fade_start(test_speed_mode, LEDC_CHANNEL_0, LEDC_FADE_NO_WAIT));
-    vTaskDelay(1000 / portTICK_RATE_MS);
-    TEST_ASSERT_EQUAL_INT32(ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0), 0);
+    // duty should not be too far from initial value
+    TEST_ASSERT_INT32_WITHIN(20, 4000, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
+    vTaskDelay(210 / portTICK_PERIOD_MS);
+    TEST_ASSERT_EQUAL_INT32(0, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
 
-    //deinitial fade service
+    //deinitialize fade service
     ledc_fade_func_uninstall();
 }
 
-TEST_CASE("LEDC fade with step(logic analyzer)", "[ledc][test_env=UT_T1_LEDC]")
+TEST_CASE("LEDC fade with step", "[ledc]")
 {
-#ifdef CONFIG_FREERTOS_CHECK_PORT_CRITICAL_COMPLIANCE
-    return;
-#endif
-
-#ifdef CONFIG_IDF_TARGET_ESP32
     const ledc_mode_t test_speed_mode = LEDC_HIGH_SPEED_MODE;
-#elif defined CONFIG_IDF_TARGET_ESP32S2BETA
-    const ledc_mode_t test_speed_mode = LEDC_LOW_SPEED_MODE;
-#endif
-    ledc_channel_config_t ledc_ch_config = {
-        .gpio_num = PULSE_IO,
-        .speed_mode = test_speed_mode,
-        .channel  = LEDC_CHANNEL_0,
-        .intr_type = LEDC_INTR_DISABLE,
-        .timer_sel = LEDC_TIMER_0,
-        .duty = 0,
-        .hpoint = 0,
-    };
-    TEST_ESP_OK(ledc_channel_config(&ledc_ch_config));
-
-    ledc_timer_config_t ledc_time_config = {
-        .speed_mode = test_speed_mode,
-        .duty_resolution = LEDC_TIMER_13_BIT,
-        .timer_num = LEDC_TIMER_0,
-        .freq_hz = 5000,
-        .clk_cfg = LEDC_USE_APB_CLK,
-    };
-    TEST_ESP_OK(ledc_timer_config(&ledc_time_config));
+    fade_setup();
 
-    //initialize fade service.
-    TEST_ESP_OK(ledc_fade_func_install(0));
-
-    TEST_ESP_OK(ledc_set_fade_with_step(test_speed_mode, LEDC_CHANNEL_0, 4000, 2, 1));
+    TEST_ESP_OK(ledc_set_fade_with_step(test_speed_mode, LEDC_CHANNEL_0, 4000, 4, 1));
     TEST_ESP_OK(ledc_fade_start(test_speed_mode, LEDC_CHANNEL_0, LEDC_FADE_WAIT_DONE));
-    vTaskDelay(1000 / portTICK_RATE_MS);
-    TEST_ASSERT_EQUAL_INT32(ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0), 4000);
+    TEST_ASSERT_EQUAL_INT32(4000, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
 
-    TEST_ESP_OK(ledc_set_fade_with_step(test_speed_mode, LEDC_CHANNEL_0, 0, 4, 2));
+    TEST_ESP_OK(ledc_set_fade_with_step(test_speed_mode, LEDC_CHANNEL_0, 0, 4, 1));
     TEST_ESP_OK(ledc_fade_start(test_speed_mode, LEDC_CHANNEL_0, LEDC_FADE_NO_WAIT));
-    vTaskDelay(1000 / portTICK_RATE_MS);
-    TEST_ASSERT_EQUAL_INT32(ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0), 0);
+    // duty should not be too far from initial value
+    TEST_ASSERT_INT32_WITHIN(20, 4000, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
+    vTaskDelay(525 / portTICK_PERIOD_MS);
+    TEST_ASSERT_EQUAL_INT32(0, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
 
     //scaler=0 check
     TEST_ASSERT(ledc_set_fade_with_step(test_speed_mode, LEDC_CHANNEL_0, 4000, 0, 1) == ESP_ERR_INVALID_ARG);
 
-    //deinitial fade service
+    //deinitialize fade service
+    ledc_fade_func_uninstall();
+}
+
+TEST_CASE("LEDC fast switching duty with fade_wait_done", "[ledc]")
+{
+    const ledc_mode_t test_speed_mode = LEDC_HIGH_SPEED_MODE;
+    fade_setup();
+
+    // fade function will block until fading to the target duty
+    int64_t fade_start, fade_stop;
+    fade_start = esp_timer_get_time();
+    TEST_ESP_OK(ledc_set_fade_with_time(test_speed_mode, LEDC_CHANNEL_0, 4000, 200));
+    TEST_ESP_OK(ledc_fade_start(test_speed_mode, LEDC_CHANNEL_0, LEDC_FADE_WAIT_DONE));
+    TEST_ASSERT_EQUAL_INT32(4000, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
+    TEST_ESP_OK(ledc_set_fade_with_time(test_speed_mode, LEDC_CHANNEL_0, 1000, 150));
+    TEST_ESP_OK(ledc_fade_start(test_speed_mode, LEDC_CHANNEL_0, LEDC_FADE_WAIT_DONE));
+    TEST_ASSERT_EQUAL_INT32(1000, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
+    fade_stop = esp_timer_get_time();
+    int time_ms = (fade_stop - fade_start) / 1000;
+    TEST_ASSERT_TRUE(fabs(time_ms - 350) < 20);
+
+    // next duty update will not take place until last fade reaches its target duty
+    TEST_ESP_OK(ledc_set_fade_with_time(test_speed_mode, LEDC_CHANNEL_0, 4000, 200));
+    TEST_ESP_OK(ledc_fade_start(test_speed_mode, LEDC_CHANNEL_0, LEDC_FADE_WAIT_DONE));
+    TEST_ASSERT_EQUAL_INT32(4000, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
+    TEST_ESP_OK(ledc_set_duty(test_speed_mode, LEDC_CHANNEL_0, 500));
+    TEST_ESP_OK(ledc_update_duty(test_speed_mode, LEDC_CHANNEL_0));
+    vTaskDelay(5 / portTICK_PERIOD_MS);
+    TEST_ASSERT_EQUAL_INT32(500, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
+
+    //deinitialize fade service
+    ledc_fade_func_uninstall();
+}
+
+TEST_CASE("LEDC fast switching duty with fade_no_wait", "[ledc]")
+{
+    const ledc_mode_t test_speed_mode = LEDC_HIGH_SPEED_MODE;
+    fade_setup();
+
+    // fade function returns immediately, but next fade still needs to wait for last fade ends
+    int64_t fade_start, first_fade_complete;
+    fade_start = esp_timer_get_time();
+    TEST_ESP_OK(ledc_set_fade_with_time(test_speed_mode, LEDC_CHANNEL_0, 4000, 200));
+    TEST_ESP_OK(ledc_fade_start(test_speed_mode, LEDC_CHANNEL_0, LEDC_FADE_NO_WAIT));
+    TEST_ASSERT_LESS_THAN(4000, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
+    TEST_ESP_OK(ledc_set_fade_with_time(test_speed_mode, LEDC_CHANNEL_0, 1000, 150));
+    TEST_ESP_OK(ledc_fade_start(test_speed_mode, LEDC_CHANNEL_0, LEDC_FADE_NO_WAIT));
+    first_fade_complete = esp_timer_get_time();
+    // duty should not be too far from first fade target duty
+    TEST_ASSERT_INT32_WITHIN(20, 4000, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
+    int time_ms = (first_fade_complete - fade_start) / 1000;
+    TEST_ASSERT_TRUE(fabs(time_ms - 200) < 20);
+    vTaskDelay(158 / portTICK_PERIOD_MS);
+    TEST_ASSERT_EQUAL_INT32(1000, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
+
+    // next duty update will not take place until last fade reaches its target duty
+    TEST_ESP_OK(ledc_set_fade_with_time(test_speed_mode, LEDC_CHANNEL_0, 4000, 200));
+    TEST_ESP_OK(ledc_fade_start(test_speed_mode, LEDC_CHANNEL_0, LEDC_FADE_NO_WAIT));
+    TEST_ASSERT_LESS_THAN(4000, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
+    TEST_ESP_OK(ledc_set_duty(test_speed_mode, LEDC_CHANNEL_0, 500));
+    TEST_ESP_OK(ledc_update_duty(test_speed_mode, LEDC_CHANNEL_0));
+    vTaskDelay(5 / portTICK_PERIOD_MS);
+    TEST_ASSERT_EQUAL_INT32(500, ledc_get_duty(test_speed_mode, LEDC_CHANNEL_0));
+
+    //deinitialize fade service
     ledc_fade_func_uninstall();
 }