// Periodically check Bluetooth (non-blocking) if (bluetooth.available()) char cmd = bluetooth.read(); if (cmd == 'G') gps.listen(); // Switch back to GPS
1. Introduction: The Hardware Limitation Every Arduino enthusiast eventually hits the wall: "I only have one hardware serial port (pins 0 and 1), but I need to connect two serial devices."
void setup() Serial.begin(9600); // Debug console gps.begin(9600); bluetooth.begin(38400); // Common HC-05 default gps.listen(); // Listen to GPS first softwareserial.h library
port1.listen(); // Switch back
You can create multiple instances, but only one can receive at a time . The active receiver is set by the last call to listen() . // Periodically check Bluetooth (non-blocking) if (bluetooth
Bidirectional Communication with Collision Avoidance Since SoftwareSerial is half-duplex, implement a simple protocol:
SoftwareSerial port1(2, 3); SoftwareSerial port2(4, 5); void setup() port1.begin(9600); port2.begin(9600); port1.listen(); // port1 is active implement a simple protocol: SoftwareSerial port1(2
The classic Arduino Uno, Nano, and Mega 2560 (for its first few ports) have dedicated hardware UARTs (Universal Asynchronous Receiver-Transmitters). However, hardware UARTs are limited in number. Once you connect a GPS module, a Bluetooth module, and a debug console simultaneously, you run out of ports.