Softwareserial.h Library ((install)) <2026 Release>

void loop() if (port1.available()) // Process port1 data

// Must call listen() on active port regularly if (!gps.isListening()) gps.listen(); softwareserial.h library

// Switch to port2 briefly port2.listen(); if (port2.available()) // Process port2 data void loop() if (port1

Bidirectional Communication with Collision Avoidance Since SoftwareSerial is half-duplex, implement a simple protocol: | | read() | Reads one byte (-1 if none)

#include <SoftwareSerial.h> For ESP8266/ESP32, note that they have a different SoftwareSerial implementation (often renamed or not available due to better hardware serial options). Constructor SoftwareSerial mySerial(RX_pin, TX_pin); // Example: RX on pin 10, TX on pin 11 SoftwareSerial gpsSerial(10, 11); Essential Methods | Method | Description | |--------|-------------| | begin(baud) | Initializes the software serial port. | | available() | Returns number of bytes ready to read. | | read() | Reads one byte (-1 if none). | | write(data) | Sends a byte (or string via print() / println() ). | | listen() | Enables this port for reception (if multiple ports exist). | | isListening() | Checks if this port is active. | | overflow() | Returns true if data was lost due to buffer overflow (64-byte buffer). | Simple Example: GPS Module #include <SoftwareSerial.h> SoftwareSerial gps(10, 11); // RX=10, TX=11

SoftwareSerial.h is a powerful but fragile tool. It turns any two pins into a serial port, enabling multi-device Arduino projects on a budget. However, its software-timed nature means it cannot replace hardware serial for high-speed, high-reliability, or interrupt-heavy applications.