esp-idf: ESP32-S3 Blink example does not work (IDFGH-6927)

In case this helps others using the N32R8V variant of the ESP32-S3-DevKitC-1 (v 1.1), I found that the CONFIG_BLINK_GPIO needs to be using pin 38, not the default 48. You can set this using the terminal cmd idf.py menuconfig, selecting “Example Configuration” and changing “Blink GPIO Number” to 38.

Finally got the reason why it failed. The board (ESP32-S3-DevKitC-1 v1.0, N32R8V) from Espressif may have problem.

The waveform from ESP32-S3, measured from the LED control signal pin solder pad (not from the header pin). PWM High is too low at around 1.88V https://ibb.co/7Nry8F2

For ESP32-S2, it is around 3.1V with the same testing condition above. https://ibb.co/ZSD2TTL

The two waveforms overlapped image: https://ibb.co/5Ywxf87

Do recent boards have similar problem? The board is also not recognized by RainMaker during claiming procedure.

Can you also test it using the LED Strip Example?

Be sure to configure the GPIO to 48 in case of the ESP32-S3-DevKitC-1.

While testing it on the LOLIN S3 Pro, I had to enable the USB CDC On Boot and select the ESP32S3 Dev Module instead of LOLIN S3 Pro, and also the LED, at least for me, doesn’t seem to be a RGB LED but a GRB LED. So, I had to do some changes:

#define RGB_PIN 38

void setup() {
  neopixelWrite(RGB_PIN, 0, 0, 0);  // ALWAYS TURN NEOPIXEL OFF AT FIRST !!
  Serial.begin(2000000);
}

void loop() {
  Serial.println("ALL COLORS!");
  neopixelWrite(RGB_PIN, RGB_BRIGHTNESS, RGB_BRIGHTNESS, RGB_BRIGHTNESS);  // Red
  delay(1000);
  Serial.println("OFF!");
  neopixelWrite(RGB_PIN, 0, 0, 0);  // Off / black
  delay(1000);
  Serial.println("GREEN!");
  neopixelWrite(RGB_PIN, RGB_BRIGHTNESS, 0, 0);  // GREEN
  delay(1000);
  Serial.println("RED!");
  neopixelWrite(RGB_PIN, 0, RGB_BRIGHTNESS, 0);  // RED
  delay(1000);
  Serial.println("BLUE!");
  neopixelWrite(RGB_PIN, 0, 0, RGB_BRIGHTNESS);  // BLUE
  delay(1000);
  Serial.println("OFF!");
  neopixelWrite(RGB_PIN, 0, 0, 0);  // Off / black
  delay(1000);
}

I had the same issue, I tried example projects as is, didn’t work. The solution is simple for dev boards, you can just look at your board above RGB LED itself, there is a text with GPIO where this LED is connected. Update in BlinkRGB example RGB_BUILTIN to your pin number and that’s it.

#define RGB_PIN 38

void setup() {
  // No need to initialize the RGB LED
}

// the loop function runs over and over again forever
void loop() {
  neopixelWrite(RGB_PIN,RGB_BRIGHTNESS,RGB_BRIGHTNESS,RGB_BRIGHTNESS); // Red
  delay(1000);
  neopixelWrite(RGB_PIN,0,0,0); // Off / black
  delay(1000);

  neopixelWrite(RGB_PIN,RGB_BRIGHTNESS,0,0); // Red
  delay(1000);
  neopixelWrite(RGB_PIN,0,RGB_BRIGHTNESS,0); // Green
  delay(1000);
  neopixelWrite(RGB_PIN,0,0,RGB_BRIGHTNESS); // Blue
  delay(1000);
  neopixelWrite(RGB_PIN,0,0,0); // Off / black
  delay(1000);
}

My board was not working too, but after I connected it (image below), and now it’s working.

code: https://github.com/espressif/arduino-esp32/blob/master/libraries/ESP32/examples/GPIO/BlinkRGB/BlinkRGB.ino

I’ve figured out, I had to add an additional line #define RGB_BUILTIN 38 and now it works 👍

@maned3v The LED on this board is not a simple LED, but it is a NeoPixel LED, which needs to be programmed via a serial interface. I guess the Arduino init code (which is not called from your VSC code) does the programming, that’s why it works. You need to initialize the LED with the appropriate function, and use neopixelWrite instead of digitalWrite.

@bhoffman17 Please note that while the LED power supply voltage is 3.3V (so the LED is bright), but the communication line is only 1.8V. According to the datasheet this pin belongs to the VDD_SPI power domain, which is 1.8V on this particular board (ESP32-S3-DevKitC-1-N32R8V). Other boards with 3.3V SPI flash voltage are not affected.

The issues is related with 1.8v VDD_SPI, the ESP32-S3-WROOM-2 is 1.8v SPI Flash and PSRAM, the GPIO 48 & 47 is powered from VDD_SPI and it can’t be changed to other power domain, so the voltage of GPIO48 & 47 is limited on 1.8v .

@pedrominatel Yes, the configuration is correct, GPIO48 is selected. The signal on the pin is correct, just the level is too low. Please find attached the sdkconfig file.

sdkconfig.zip

Can you check the value of the R17? Is the one close to the RGB LED:

It should be 0R. You can try to remove it and make a soldering jumper for testing.

With both external WB2812B and on-board LED are connected to GPIO48. As I said before, on-board LED always works while external one never works.

Then I remove external one from GPIO48. The on-board LED is not normal immediately.

PS: Connecting the external strip back to GPIO48, the on-board one works again.

PPS: I found in order to make on-board LED work, 5V must be supplied to the external strip. Without 5V and only control and ground connected to the board does not help.

@pedrominatel I have only one ESP32-S3-DevKitC (N32R8V) which was ordered in Feb from Espressif China. But the factory pre-loaded firmware works perfectly to control the RGB LED with different color. And the LED works exactly like ESP32-S2 boards pre-loaded firmware.

I will try. to test LED Strip example.