Serial Terminal library for Arduino

This is a universal Serial Terminal library for Arduino to parse ASCII commands and arguments.

Hardware

Any Arduino hardware with a serial port, such as:

Arduino:

• UNO
• Nano
• Micro
• Pro or Pro Mini
• Mega or Mega2560
• Leonardo

Other targets:

• DUE
• ESP8266
• ESP32
• SAMD21
• STM32F1

Examples

Arduino IDE | Examples | Erriez Serial Terminal |

• ErriezSerialTerminal

Documentation

• Online HTML
• Download PDF

Usage

Initialization

Create a Serial Terminal object. This can be initialized with optional newline and delimiter characters.

Default newline character: '\n' Default delimiter character: Space

#include <ErriezSerialTerminal.h>

// Newline character '\r' or '\n'
char newlineChar = '\n'; 
// Separator character between commands and arguments
char delimiterChar = ' ';

// Create serial terminal object
SerialTerminal term(newlineChar, delimiterChar);


void setup()
{
    // Initialize serial port
    Serial.begin(115200);
    
    // Initialize the built-in LED
    pinMode(LED_BUILTIN, OUTPUT);
    digitalWrite(LED_BUILTIN, LOW);
}

Register new commands

Commands must be registered at startup with a corresponding callback handler . This registers the command only, excluding arguments.

The callback handler will be called when the command has been received including the newline character.

An example of registering multiple commands:

void setup()
{
    ...

    // Add command callback handlers
    term.addCommand("?", cmdHelp);
    term.addCommand("help", cmdHelp);
    term.addCommand("on", cmdLedOn);
    term.addCommand("off", cmdLedOff);
}

void cmdHelp()
{
    // Print usage
    Serial.println(F("Serial terminal usage:"));
    Serial.println(F("  help or ?          Print this usage"));
    Serial.println(F("  on                 Turn LED on"));
    Serial.println(F("  off                Turn LED off"));
}

void cmdLedOn()
{
    // Turn LED on
    Serial.println(F("LED on"));
    digitalWrite(LED_BUILTIN, HIGH);
}

void cmdLedOff()
{
    // Turn LED off
    Serial.println(F("LED off"));
    digitalWrite(LED_BUILTIN, LOW);
}

Set default handler

Optional: The default handler will be called when the command is not recognized.

void setup()
{   
    ...

    // Set default handler for unknown commands
    term.setDefaultHandler(unknownCommand);
}

void unknownCommand(const char *command)
{
    // Print unknown command
    Serial.print(F("Unknown command: "));
    Serial.println(command);
}

Read from serial port

Read from the serial port in the main loop:

void loop()
{
    // Read from serial port and handle command callbacks
    term.readSerial();
}

Get next argument

Get pointer to next argument in serial receive buffer:

char *arg;

// Get next argument
arg = term.getNext();
if (arg != NULL) {
    Serial.print(F("Argument: "));
    Serial.println(arg);
} else {
    Serial.println(F("No argument"));
}

Get remaining characters

Get pointer to remaining characters in serial receive buffer:

char *arg;

// Get remaining characters
arg = term.getRemaining();
if (arg != NULL) {
    Serial.print(F("Remaining: "));
    Serial.println(arg);
}

Clear buffer

Optional: The serial receive buffer can be cleared with the following call:

term.clearBuffer();

Enable/Disable Character Echoing

Optional: Allow for any entered charecters to be printed back to the Serial interface. This is useful for terminal programs like PuTTY. Supports both backspace characters, ^H and ^127.

term.setSerialEcho(true); //Enable Character Echoing

Set Post Command Handler

Optional: Add a function to be called AFTER a command has been handled.

void setup()
{   
    ...

    // Set handler to be run AFTER a command has been handled.
    term.setPostCommandHandler(postCommandHandler);
}

void setPostCommandHandler()
{
    // Print '> ' for a primitive user UI
    Serial.print(F("> "));
}

Library configuration

SerialTerminal.h contains the following configuration macro's:

• ST_RX_BUFFER_SIZE : The default serial receive buffer size is 32 Bytes. This includes the command and arguments, excluding the '\0' character.
• ST_NUM_COMMAND_CHARS: The default number of command characters is 8 Bytes, excluding the '\0' character.

Library dependencies

• None.

Library installation

Please refer to the Wiki page.

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