Adafruit ESP32-S3 TFT ext USB pwr problem

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1

Hi, two days ago received from your company the ordered Adafruit ESP32-S3 TFT (verA).
Using Arduino IDE v2.3.4. with latest updates. Created a sketch to show data from a I2C connected MCP9808 sensor (connected via the Stemma QT/Qwiic connector). Works OK when powered from PC USB or a 3.7V battery. However does not work from an external 5V DC Power source. I have also an Adafruit Feather ESP32-S2 TFT flashed with Circuitpython. That board runs OK on that same external 5V DC Power source.

In the sketch I have the following commands:
// turn on the TFT / I2C power supply
pinMode(TFT_I2C_POWER, OUTPUT);
digitalWrite(TFT_I2C_POWER, HIGH);

Using a USB Volt / Ampère meter device, I saw that on the PC USB the Voltage was: 5.157V, and the current drawn: 0.062A. I saw that on the external power supply, the Voltage was:: 5.033V and the current drawn: 0.062A

I checked for possible solder issues. Re-touched with the solder-iron various Pins that I assumed to be important to check.

Any ideas to solve this problem?

2

I just flashed a factory demo. That runs on external 5V supply. Now I am going to see what are the differences between my sketch and the factory demo that could cause the problem.
Danh on Discord/Adafruit channel, tipped me that maybe there was a waiting for serial command in my sketch. I checked. Yes, there was this:

void setup() {
  Serial.begin(115200);
  while (! Serial) delay(10);

I commented-out the “while” line and voilá!, the sketch is running while the board is powered from an external power supply! Problem solved!