RTL8720DN Serial communication

Technical Discussion
1

Hi

I am trying to get UART working across two RTL8720DN boards.

I am using one RTL8720DN as the master and the second RTL8720DN as the slave. Just wondering if the code I have would work.

#include <SoftwareSerial.h>

#define BLUE_LED            PA13   // also known as PA13 in BW16 module (see variant.h)

SoftwareSerial Serial2(PA30, PA26); // RX, TX

void setup() {
  // put your setup code here, to run once:
  Serial2.begin(115200);            // initialize UART with the second board with baud rate of 9600

}

void loop() {
  // put your main code here, to run repeatedly:
  Serial2.println(3);
  delay(5000);
}

You can see that I have chosen two random pins and allocated them as serial pins. Is this okay or should I use the specified Serial RX (PB2) and Serial TX (PB1) for serial communication between the two boards?

Thanks.

2

Hi you should try sticking to the hardware UART pins, otherwise this might not work at all

3

Hi

I appreciate the quick response. I have currently routed PB1 to PA7 and PB2 to PA8 in order to flash code from the Arduino IDE. Can I still use PB1 and PB2 for serial communication to another board?

4

Hi, for BW16 dev board, there are 2 sets of UART you can use,

LOG UART:

  • PA_7
  • PA_8

UART1

  • PB_1
  • PB_2

These 2 can be used independently. However, if you have routed UART1 to LOG UART, then you need a seperate USB-to-Serial module (eg FTDI, CH340, CP2102) to connect to LOG UART for printing out serial msg, then you can use the other set for serial communication