Fix ledc panic’ed when wrong setup of frequency and bit width (espressif#6371)

* Fixed LEDC panic when wrong bit widht / frequency set.

* Fixed ledc example to be working on all SOCs

Author: P-R-O-C-H-Y

cores/esp32/esp32-hal-ledc.c

@@ -56,10 +56,11 @@ uint8_t channels_resolution[LEDC_CHANNELS] = {0};
 
 double ledcSetup(uint8_t chan, double freq, uint8_t bit_num)
 {
-    if(chan >= LEDC_CHANNELS){
-        log_e("No more LEDC channels available! You can have maximum %u", LEDC_CHANNELS);
+    if(chan >= LEDC_CHANNELS || bit_num > LEDC_MAX_BIT_WIDTH){
+        log_e("No more LEDC channels available! (maximum %u) or bit width too big (maximum %u)", LEDC_CHANNELS, LEDC_MAX_BIT_WIDTH);
         return 0;
     }
+
     uint8_t group=(chan/8), timer=((chan/2)%4);
 
     ledc_timer_config_t ledc_timer = {
@@ -69,9 +70,12 @@ double ledcSetup(uint8_t chan, double freq, uint8_t bit_num)
         .freq_hz          = freq,
         .clk_cfg          = LEDC_DEFAULT_CLK
     };
-    ledc_timer_config(&ledc_timer);
+    if(ledc_timer_config(&ledc_timer) != ESP_OK)
+    {
+        log_e("ledc setup failed!");
+        return 0;
+    }
     channels_resolution[chan] = bit_num;
-
     return ledc_get_freq(group,timer);
 }
 
@@ -95,7 +99,7 @@ void ledcWrite(uint8_t chan, uint32_t duty)
 
 uint32_t ledcRead(uint8_t chan)
 {
-     if(chan >= LEDC_CHANNELS){
+    if(chan >= LEDC_CHANNELS){
         return 0;
     }
     uint8_t group=(chan/8), channel=(chan%8);
@@ -130,7 +134,12 @@ double ledcWriteTone(uint8_t chan, double freq)
         .freq_hz          = freq, 
         .clk_cfg          = LEDC_DEFAULT_CLK
     };
-    ledc_timer_config(&ledc_timer);
+
+    if(ledc_timer_config(&ledc_timer) != ESP_OK)
+    {
+        log_e("ledcSetup failed!");
+        return 0;
+    }
     channels_resolution[chan] = 10;
 
     double res_freq = ledc_get_freq(group,timer);
@@ -153,7 +162,7 @@ double ledcWriteNote(uint8_t chan, note_t note, uint8_t octave){
 
 void ledcAttachPin(uint8_t pin, uint8_t chan)
 {
-     if(chan >= LEDC_CHANNELS){
+    if(chan >= LEDC_CHANNELS){
         return;
     }
     uint8_t group=(chan/8), channel=(chan%8), timer=((chan/2)%4);
@@ -177,7 +186,8 @@ void ledcDetachPin(uint8_t pin)
 
 double ledcChangeFrequency(uint8_t chan, double freq, uint8_t bit_num)
 {
-     if(chan >= LEDC_CHANNELS){
+    if(chan >= LEDC_CHANNELS || bit_num > LEDC_MAX_BIT_WIDTH){
+        log_e("LEDC channel not available! (maximum %u) or bit width too big (maximum %u)", LEDC_CHANNELS, LEDC_MAX_BIT_WIDTH);
         return 0;
     }
     uint8_t group=(chan/8), timer=((chan/2)%4);
@@ -189,9 +199,13 @@ double ledcChangeFrequency(uint8_t chan, double freq, uint8_t bit_num)
         .freq_hz          = freq, 
         .clk_cfg          = LEDC_DEFAULT_CLK
     };
-    ledc_timer_config(&ledc_timer);
-    channels_resolution[chan] = bit_num;
 
+    if(ledc_timer_config(&ledc_timer) != ESP_OK)
+    {
+        log_e("ledcChangeFrequency failed!");
+        return 0;
+    }
+    channels_resolution[chan] = bit_num;
     return ledc_get_freq(group,timer);
 }
 

libraries/ESP32/examples/AnalogOut/LEDCSoftwareFade/LEDCSoftwareFade.ino

@@ -13,8 +13,8 @@
 // use first channel of 16 channels (started from zero)
 #define LEDC_CHANNEL_0     0
 
-// use 13 bit precission for LEDC timer
-#define LEDC_TIMER_13_BIT  13
+// use 12 bit precission for LEDC timer
+#define LEDC_TIMER_12_BIT  12
 
 // use 5000 Hz as a LEDC base frequency
 #define LEDC_BASE_FREQ     5000
@@ -28,16 +28,16 @@ int fadeAmount = 5;    // how many points to fade the LED by
 // Arduino like analogWrite
 // value has to be between 0 and valueMax
 void ledcAnalogWrite(uint8_t channel, uint32_t value, uint32_t valueMax = 255) {
-  // calculate duty, 8191 from 2 ^ 13 - 1
-  uint32_t duty = (8191 / valueMax) * min(value, valueMax);
+  // calculate duty, 4095 from 2 ^ 12 - 1
+  uint32_t duty = (4095 / valueMax) * min(value, valueMax);
 
   // write duty to LEDC
   ledcWrite(channel, duty);
 }
 
 void setup() {
   // Setup timer and attach timer to a led pin
-  ledcSetup(LEDC_CHANNEL_0, LEDC_BASE_FREQ, LEDC_TIMER_13_BIT);
+  ledcSetup(LEDC_CHANNEL_0, LEDC_BASE_FREQ, LEDC_TIMER_12_BIT);
   ledcAttachPin(LED_PIN, LEDC_CHANNEL_0);
 }