[RTL8722CSM] [RTL8722DM] UART - Send and Receive

Materials

  • AmebaD[AMB21 / AMB22] x 1

  • TTL USB to Serial module x 1

Steps

UART is a very versatile communication protocol and almost an essential part of a microcontroller. A TTL USB to Serial module is an IC that helps to translate UART signal to USB signal so that we can see uart log printed on our PC. This module is often found on many development boards, including ameba. However, the module on Ameba is reserved for LOG UART and Firmware uploading, that is why we need a separate module to communicate between ameba and PC.

There are currently 2 sets of UART available to MicroPython users and they are:

Unit

tx

RX

0

PA_21

PA_22

3

PA_26

PA_25
Here we are using unit 0 to demonstrate how uart works on ameba.
Connect TTL module to PA_21 and PA_22 as shown below,

image1

Then, copy and paste the following code line by line into REPL to see its effect.

1from machine import UART
2uart = UART(tx="PA_21", rx= "PA_22")
3uart.init()
4uart.write('hello')
5uart.read(5) # read up to 5 bytes