The Yoto Mini does not have a USB to serial converter chip to access the ESP32 via USB. However, it does have the programming pins broken out at the top edge of the PCB. To make uploading firmware easier, you can solder together a quick programmer breakout.

Parts

Circuit Diagram

The programmer circuit can be soldered to a 1/4 size perma-proto board.

ESP32

• Enable (EN) to BOOT button (red wire)
• Reset (RST) to 10K resistor to RESET button (black wire)
• TXD to FTDI RX (yellow wire)
• RXD to FTDI TX (green wire)
• GND to FTDI GND (blue wire)
• 3.3V to TLV62569 3V (red wire)

FTDI/USB Serial

• GND to TLV62569 GND (black wire)
• GND to BOOT and RESET button GND (black wires)
• 5V to TLV62569 Vin (orange wire)

Solder to the Yoto Player

Five of the six needed pins are broken out along the top edge of the Yoto Mini PCB:

• GND, RXD, TXD, RST and EN

Solder one cable pair to the five broken out pins along the edge.

The last wire in the cable bundle is for 3.3V. You will need to either solder to the 3.3V test point on the PCB or directly to the 3.3V pin on the ESP32. I recommend the 3.3V pin for stability.

Use

After connecting the Yoto Mini to the programmer board, connect the USB serial cable to the programmer. Plug the USB cable into your computer. You can now put the ESP32 into bootloader mode by holding down the BOOT button, pressing the RESET button and then releasing the BOOT button. Now you're able to access the ESP32 over USB serial.