You don't have to press any buttons. I'm currently using the ESP32 as a main MCU and programming it works if you follow those steps (I will repeat all of them):
- Make sure you have the WiFiNINA Library and SAMD / ESP32 Cores installed in the IDE
- Set the board to Arduino Nano 33 IoT
- Open the sketch Examples -> WiFiNINA -> Tools -> SerialNINAPassthrough and upload it to the board
- Change the board to:
ESP32 Dev Module and adjust the following:
- Flash Size: 2MB
- Flash Mode: DIO
- Partition Scheme: minimal
OR simply use:
u-blox NINA-W10 series which has the settings already configured.
- Open Examples -> BluetoothSerial -> SerialToSerialBT and upload it to the same COM port, but making sure one of the above boards is selected
(I deleted the delay(20) from the sketch to speed up the communication) - Now change the board back to Nano and upload the sketch you want, you can use SerialNina serial to send data through the NINA module
For me this process works correctly, just make sure you don't have the ports opened somewhere else.