uploading upy files / firmware without USB

All ESP32 boards running MicroPython.
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bjames28
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Joined: Fri May 17, 2019 12:55 pm

uploading upy files / firmware without USB

Post by bjames28 » Thu Feb 18, 2021 1:51 pm

Hi All,

I'd like to use the ESP32 chip on custom made PCB without USB connection.
What are the possibilities to upload the micropython firmware and eventually later uploading .py files?
JTAG or UART maybe?

Thank you for any guidance in advance

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Roberthh
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Joined: Sat May 09, 2015 4:13 pm
Location: Rhineland, Europe

Re: uploading upy files / firmware without USB

Post by Roberthh » Thu Feb 18, 2021 2:51 pm

The standard ESP32 does not support USB itself. Instead, many ESP32 boards are equipped with a UART/USB bridge. Therefore, you can connect any USB/UART bridge to UART0 (GPIO 1 and 3) and use one the the many tools to communicate with the device, starting with pyboard.py, rshell, Thonny, ...... That link would also be used for uploading firmware. For that, GPIO0 must also be accessible. You may also use WiFi for the connection using WebREPL. That also allows exchanging files. rshell and Thonny also support WiFi connections.Python based FTP and Telnet servers are available too,

FTP: https://github.com/robert-hh/FTP-Server ... 2-and-PYBD
Telnet: https://github.com/cpopp/MicroTelnetServer

bjames28
Posts: 7
Joined: Fri May 17, 2019 12:55 pm

Re: uploading upy files / firmware without USB

Post by bjames28 » Thu Feb 18, 2021 4:09 pm

Hi Robert,

Thanks for the quick reply.
I can't use any ESP32 board with USB bridge just the "pure" ESP32 chip alone. Therefore I thought such https://www.aliexpress.com/item/33028710111.html?spm adapter board (with USB bridge) could be used to flash the all my ESP32 chips initially, and later changes can be made over WiFi or OTA updates in the destination PCBs

I know Thonny, that's a great tool I use often.

I've read about usage of JTAG , but this was pyboard with STM chip.

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Roberthh
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Location: Rhineland, Europe

Re: uploading upy files / firmware without USB

Post by Roberthh » Thu Feb 18, 2021 7:21 pm

I do not know if your board is already finished. If not. it seems useful for me to have a 4 pin connector (or just pads) exposing GND, GPIO0, GPIO1 and GPIO3. Using that connector reflashing the chip is possible, if anything else fails.

bjames28
Posts: 7
Joined: Fri May 17, 2019 12:55 pm

Re: uploading upy files / firmware without USB

Post by bjames28 » Fri Feb 19, 2021 3:14 pm

Hi Robert,

Thanks for the great hint, we will include those pins into the PCB design.

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