Just starting with Software Serial.
I found that in order to print out an ASCII character from the incoming byte I need to substract 128 from it. Why is that?
#include <SoftwareSerial.h>
// Pin 0 connected to pin 3
// Pin 1 connected to pin 2
SoftwareSerial SWSerial(2, 3); // RX, TX
void setup()
{
Serial.begin(9600);
SWSerial.begin(9600);
SWSerial.write("SW Serial here");
}
void loop()
{
int incomingByte;
if (Serial.available())
{
incomingByte = Serial.read();
// say what you got:
Serial.print("I received: ");
Serial.write(incomingByte-128);
Serial.println();
}
}
I received: S
I received: W
I received:
I received: S
I received: e
I received: r
I received: i
I received: a
I received: l
I received:
I received: h
I received: e
I received: r
I received: e
I am not even using Serial.print
The code does write -> read -> write
write is in bytes and read is in integers, so I guess that's why I need to substract or truncate the incoming data?
Use SWSerial.print() instead, and declare incomingByte as "char", not "int".
SWSerial.write("SW Serial here");
From the Arduino Reference:
Serial.write()
Description
Writes binary data to the serial port. This data is sent as a byte or series of bytes; to send the characters representing the digits of a number use the print() function instead.
My guess is that whatever is sending to your Serial input is sending 7 data bits. By default, Serial reads 8 data bits. That would cause the Stop Bit to be read as an 8th data bit. Try changing "Serial.begin(9600);" to "Serial.begin(9600, 7N1);". Then you should remove the "-128"
Your sketch sets up SoftwareSerial and then doesn't use it at all.
@johnwasser I am letting the Arduino talk to itself SW serial to HW serial, just to see how it works. So hopefully, I shouldn't need to worry about stop bits?
