Hi there. I've been bashing my head against trying to understand serial transmission on my Arduino Uno for the past couple days. I've got some code here to read from three ID-12LA RFID readers by using software serial and alternating between them using softwareserial.listen(), however the output I get is almost always nothing, or sometimes a single random character.
From my limited understanding, I think that the buffer that is holding the serial data from the ports is getting overwritten when I change the port I am listening to, but I'm unsure how else to effectively listen to three ports at once.
Some general advice on how to go about this would be greatly appreciated, as most the information I've found online is using MFRC522 readers and so doesn't apply as much here.
// Create a software serial objects for the connection to the RFID modules
SoftwareSerial rfid1 = SoftwareSerial( rx1Pin, tx1Pin );
SoftwareSerial rfid2 = SoftwareSerial( rx2Pin, tx2Pin );
SoftwareSerial rfid3 = SoftwareSerial( rx3Pin, tx3Pin );
char val1 = 0; // variable to store the data from software serial port 1
char val2 = 0; // variable to store the data from software serial port 2
char val3 = 0; // variable to store the data from software serial port 3
void setup() {
Serial.begin(9600); // connect to the serial port
while (!Serial) {
; // wait for serial port to connect. Needed for native USB port only
}
rfid1.begin(9600);
rfid2.begin(9600);
rfid3.begin(9600);
}
void loop () {
// read the software serial ports
rfid1.listen();
while(rfid1.available() > 0) {
val1 = rfid1.read();
Serial.write(val1);
}
rfid2.listen();
while(rfid2.available() > 0) {
val2 = rfid2.read();
Serial.write(val2);
}
rfid3.listen();
while(rfid3.available() > 0) {
val3 = rfid3.read();
Serial.write(val3);
}
}
