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How can I configure the USB to UART chip to set the boot and reset pins

Posted: Mon May 10, 2021 11:34 pm
by gianpcm
I can currently use the CP210x USB to UART to program the ESP32-WROOM-32, but I need to manually press the reset and the boot pushbuttons I have on my board with the module only to program it.

My goal is to make a custom board without the pushbuttons.

I noticed that my development board (ESP32 DEVKIT V1) also uses the CP210x to program the chip without the need to manually press both pushbuttons.

Could someone help with information on how to configure the CP210x?
What message is sent via USB to tell the chip to switch the EN and BOOT pins, so I can use the given USB to UART configuration software to configure my USB to UART chip?

Re: How can I configure the USB to UART chip to set the boot and reset pins

Posted: Tue May 11, 2021 4:41 am
by ESP_Sprite
You will need to add an auto-program circuit consisting of two transistors and two resistors. See for instance the DevkitC schematic, specifically the bit around Q1/Q2/R21/R22.

Re: How can I configure the USB to UART chip to set the boot and reset pins

Posted: Tue May 11, 2021 5:40 pm
by gianpcm
Thanks!