development board without USB

[brice3010]

Of all the current tens of different development boards based on a small or medium development board using an PCB module (http://esp32.net/) not a single one is without USB adapter.
Because this adapter is expensive, takes space, and is indeed only usefull when in development, I wanted to design a board that uses RX and TX from a UART module such as the FTDI breakout boards. This module needs to be fitted in its own socket on my board, and needs to be able to use auto-program and auto-reset.
In other words: when programming this board simply plug in this UART module, press "compile and download" and that is it.
Because of the way the Arduino IDE functions with the ESP32 interface however I still need to press a button after download to restart the ESP32 in normal, non-boot status.
But by using simply the DTR output I manage to get the ESP32 in programming mode, download and be ready for restart. All this on a 2x19pin breadboard friendly layout of 50x33mm, with every single ESP32 pin available.

[fovea1959]

Bruce: what did you have to do with DTR to get this to work?

[Agrume]

Hello brice,

I'm trying to use an ESP32-WROOM-32D soldered on a PCB (I made it with a standard welder so it's not a great work but it's just for try) with the 2 buttons but it doesn't work. I'm using Arduino IDE and I always get an error "A fatal error occurred: Failed to connect to ESP32: Invalid head of packet (0x74)"

Can you explain me how you did?

Thanks