Unexpected results with Serial.read()

Projects Programming
1

Hello everyone,

New to Arduino and I like it a lot. I am trying to do something simple and have not gotten results I expect. I have two Unos. I want one to send hex data over to the other and have the other show it on the serial monitor. On the send Uno I have

byte keypad_data[] = {0x00};

void setup()
{
  Serial.begin(115200);  
}

void loop()
{
  
  Serial.write((uint8_t*) keypad_data, sizeof(keypad_data));
  delay(5000);
}

I am sending only 0x00 right now so that I can see what was going on during the serial read on the other side. The data that I want is something like this {0x10, 0x8D, 0x03, 0x05, 0x07, 0xFF, 0x10, 0x03}.

On the receive Uno I have

#include <SoftwareSerial.h>

SoftwareSerial mySerial(2, 3); // RX TX

void setup()
{
  Serial.begin(115200);
  Serial.println("Hey there");
  
  mySerial.begin(115200);

}

void loop()
{ 

  if (mySerial.available() > 0)
  {
    Serial.println(mySerial.read(),BIN);
  }
}

When I do that I see in the serial monitor 10000000. Which is 0x80. I sent it 0x00. I read that serial.read() output is int. Here is a table of what I am seeing:
Send Receive(Serial.println(mySerial.read(),BIN)

0x00 10000000 -------> that is really 0x80
0x88 11001000 -------> that is really 0xC8
0xA8 11101000 -------> that is really 0xE8
0xF8 11111000 -------> that is 0xF8

Why is this happening? I can't seem to figure it out. I think its a data type thing but I am not sure. Sorry for being such a noob but this has me stumped. Thanks for you time.

2

Does software serial work at 115200? Try a slower data rate, like 9600, if the data is correct then ramp up the speed until it stops working, then back off a little.

3

@ CrossRoads
That worked! The reason I was using the 115200 is that I want to use the Arduino to sniff UART traffic between two other boards. That link is 1.8V and 115200 baud. I have ordered an Arduino Mega and the TXB0108 logic level converter from AdaFruit. I had to use the softwareSerial because I needed to be hooked up to the computer to see the output. I appreciate the help. Have a good day.

4

Okay, glad you got it working.