UART1 pins for ESP32-S2

Fermentador
Posts: 2
Joined: Mon Dec 07, 2020 3:16 pm

UART1 pins for ESP32-S2

Postby Fermentador » Mon Dec 07, 2020 3:25 pm

Hello,
In the Datasheet for ESP32-S2 I see that for UART1 pins are: RX GPIO18 and TX GPIO17.
https://www.espressif.com/sites/default ... eet_en.pdf

but here I see for ESP32-S2 UART1 using different pins . RX is GPIO21 and TX GPIO17
https://docs.espressif.com/projects/esp ... -s2-series

What is the correct pin of RX ?

ESP_Sprite
Posts: 4260
Joined: Thu Nov 26, 2015 4:08 am

Re: UART1 pins for ESP32-S2

Postby ESP_Sprite » Tue Dec 08, 2020 1:38 am

There's no discrepancy between those documents. The ESP32-S2 has a GPIO matrix that allows signals like the UART receive and transmit lines to be routed to any GPIO, even if they have 'default' GPIOs according to the datasheet. I imagine the AT firmware (as described in the second document you mention) has some reason to re-route the UART to different pins than the startup defaults (as documented in the first document).

Fermentador
Posts: 2
Joined: Mon Dec 07, 2020 3:16 pm

Re: UART1 pins for ESP32-S2

Postby Fermentador » Tue Dec 08, 2020 6:33 am

Hello,
I am using AT firmware and I followed the second documentation. UART1 communication on that particular pins doesn't work. That's why I started searching for reason.

Then you can confirm that the pinpoint in second document for AT firmware is correct.

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