Number of UARTs in ESP32

Piaceni
Posts: 1
Joined: Fri Jun 28, 2019 6:48 am

Number of UARTs in ESP32

Postby Piaceni » Fri Jun 28, 2019 11:24 am

Hi All

I am working on an IoT project using ESP32. The datasheet for ESP32 says that it has three UARTs, however some pinout images show only two UARTs. Does the ESP32 have three UARTs or are the GPIOs used for the other two UARTs apart from the main one? I am new to this board so kindly ignore my lack of technical knowledge.

Thanks. :D
Last edited by Piaceni on Mon Jul 22, 2019 5:53 pm, edited 1 time in total.

WiFive
Posts: 2795
Joined: Tue Dec 01, 2015 7:35 am

Re: Number of UARTs in ESP32

Postby WiFive » Fri Jun 28, 2019 5:10 pm

https://docs.espressif.com/projects/esp ... /uart.html

The first rule of ESP32 is use any pin you want! (Sort of)

bonmotwang
Posts: 33
Joined: Fri Apr 12, 2019 4:25 pm
Location: Canada

Re: Number of UARTs in ESP32

Postby bonmotwang » Fri Jun 28, 2019 6:33 pm

Nice rule, I like it.
I was in the same boat and had the prototype made with the impression that I can only use 2 UARTs.
I just into programming about 2 weeks. Got LCD driver working, keypad driver working. ESP32 platform is really good!

Back to UART story.
In my design, I used TXD0 and RXD0 for my RS485 communication. IO22 and IO23 (Plan to be UART1) for talking to the XBEE module.
Because UART0 was used for firmware upgrading and monitoring (I didn't know!), I cannot use it as my RS485 port anymore.

But now according to your rule and the datasheet, it seems like I have UART3 for my RS485 channel?
I can just fly wire the RS485 to any two free GPIO's.

It seems to be too good for me. LOL

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