ESP32 & Hardware UARTs

I get asked a lot about how UARTs work on the ESP32, and why I didn't expose any UARTs on the TinyPICO... well, I didn't need to expose any to allow you to use them - this the "how and why"!

#ESP32 #UART #GPIOMATRIX
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[johnouellette]

Super helpful and clearly stated...well done!... Saved me so much time

[gregclare]

Excellent video Seon, and very clearly explained. You now have a great video to just point people to, when they ask this question!
Just 1 small and totally irrelevant OCD observation @ 3:47 (so please just ignore the following, but I needed to say) :)
Remember the rule: “I before E, except after C”. ie. receivedData (not recievedData).
Sorry… I know it makes no difference, it's just a variable name, but all 5 of those “recievedData” references on the screen at once kinda overwhelmed me! LOL
Okay... don't worry... stress pill has been taken... I'm slowly backing away... nothing to see here folks... :)

[Fixaj]

is that posiible use that with Serial1?

[maicod]

Watched it and perfect and condensed but clear explanation [not UNexpected :)] I'm sure I'll look this video back up once I need to use UART.

[quantumleaper]

@UnexpectedMaker I noticed only TX & RX are connected between the two boards, but no ground/GND. Are both board's USB power sources coming from the same source and sharing a common ground themselves?

[vkfbab]

I remember reading out this. Thanks for brining it to the top of my stack! I have a project in mind to use all of the UARTs so will keep that in mind.

[jeffreyrh]

Isn't your TX and RX backwards in Serial.Begin? My Arduino IDE shows RX coming before TX.

[jerril]

Nice demo, clear explanation Seon, thanks.

[tablatronix]

Pro tip there is also an invert param you can pass to serial, to invert uart logic, say for using with optocouplers ( they invert ), I was playing with it just the other day.
I think you can also define and change these hardware uart default pins ( not sure if you can do it in boards file or not ) RXn/TXn and there is also NO_GLOBAL_SERIAL, I think it prevents init of hardware uarts

[TheEmbeddedHobbyist]

Hi Seon great vid clear and to the point. would be nice if there was a way to re-map the I/O in some way like setting configuration bits would make life easier.

[ingenierocristian]

Hi, I need to make an I2C communication between an Esp 32 and Esp8266, where can I find info about?

[TheDefpom]

I had to do remapping of the UART on an ESP32 recently, I messed up the pinout on a pcb I made (video is scheduled to be published tomorrow).

[teomanozer]

Hello, I wonder that can I use the GPIO1 and GPIO3 pins(belongs to TX, RX) as UART1 or another calling extra UART? My aim is to learn using the Rx and TX(GPIO1, GPIO3) pins as UART while I upload the code from Arduino??

[abhishekbhatia]

uart1 = UART(1, baudrate=9600, tx=33, rx=32)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ValueError: expecting a pin

can you help whats wrong here?

[fransflorenza]

in your video and some website says that default pin for uart 1 is gpio 9 and 10, but abother website says that the pin (gpio 9, 10) are recomended to not be used. is really we can use gpio 9 and 10 for serial communication?

[meagrebones]

You should have called this 'Where the bloody hell UART?"

[rbyt]

I know this is an old thread, but I’ve been struggling getting UART1 running on an ESP32-S3 module. I can’t help but notice HardwareSerial in the Arduino IDE2.2.1 shows the parameter order in Serial.begin to be: BAUD, Config, _RX_, _TX_, … . Receive and transmit pins swapped from what you show. Was this changed in the IDE in the past?

[glenb]

I am new to ESP32. Using those 30-pin modules. My question is: how about using those pins designated "input only"?
Also, are there any issues for input (rx) pins that have no internal pullup? This 30-pin module has Uart2 available, and a USB port(so assuming uart0 is taken). I have a Nextion display on GPIO 16, 17

[NotMarkKnopfler]

Can the esp32 use both uarts *and* WiFi at the same time?

[fabianrogg]

Awesome video. Do you have an example, where one esp32 sends data to another esp32 via uart?
Thx a lot