SerialCommands

An Arduino library to tokenize and parse commands received over a serial port.

Inspired by (original version): https://github.com/scogswell/ArduinoSerialCommand

This library is for handling text commands over a serial port.

Goals:

• Small footprint
• No dynamic memory allocation
• Stream class's Serial Ports
• Multiple Serial Ports callback methods
• Custom Command termination default is CR & LF
• Custom Arguments Delimeter default is SPACE
• Optional OneKey commands that are single characters without the need for additional command termination

SerialCommand object

SerialCommand creates a binding between a const string token with a callback function.

Note: SerialCommand is used in a Linked List. Do not share SerialCommand objects between SerialCommands.

#include <SerialCommands.h>

void cmd_hello(SerialCommands* sender)
{
	//Do not use Serial.Print!
	//Use sender->GetSerial this allows sharing the callback method with multiple Serial Ports
	sender->GetSerial()->println("HELLO from arduino!");
}

SerialCommand cmd_hello_("hello", cmd_hello);

OneKey commands

When sending commands from a keyboard, it is often useful to be able to use single keypresses to perform a specific action, like adjusting a motor speed up or down, for example.

To make any command a OneKey command, instantiate the command with a single character command string, and add true as a third argument:

SerialCommand cmd_faster("+", cmd_faster, true);
SerialCommand cmd_slower("-", cmd_slower, true);

The cmd_faster and cmd_slower command functions has the same signature as for multiple character commands, except that arguments are not allowed for OneKey commands (they don't make sense), so calling sender->Next() is not supported.

OneKey commands are only active when they come in as the first character, either on startup, or after processing a previous command. In other words, if another command string contains a + like set+go for example, the command callback for the one key + command will not be called when set+go is entered, and the set+go command callback will be called as expected.

Any multi character command that starts with the same character as a one key command, will however never be activated as the one key command will always consume the single character command first, i.e:

Multi char command: up
OneKey command: u

The up command will never be executed since the u will be consumed by the one key command first, which leaves the p as the remainder for the command which will not match (unless of course there is in fact a p one key or multi char command).

SerialCommands object

SerialCommands is the main object creates a binding between a Serial Port and a list of SerialCommand

#include <SerialCommands.h>

//Create a 32 bytes static buffer to be used exclusive by SerialCommands object.
//The size should accomodate command token, arguments, termination sequence and string delimeter \0 char.
char serial_command_buffer_[32];

//Creates SerialCommands object attached to Serial
//working buffer = serial_command_buffer_
//command delimeter: Cr & Lf
//argument delimeter: SPACE
SerialCommands serial_commands_(&Serial, serial_command_buffer_, sizeof(serial_command_buffer_), "\r\n", " ");

Arduino setup

void setup() 
{
	Serial.begin(57600);
	serial_commands_.AddCommand(&cmd_hello);
}

Default handler

void cmd_unrecognized(SerialCommands* sender, const char* cmd)
{
	sender->GetSerial()->print("ERROR: Unrecognized command [");
	sender->GetSerial()->print(cmd);
	sender->GetSerial()->println("]");
}
void setup() 
{
	serial_commands_.SetDefaultHandler(&cmd_unrecognized);
}

Arduino loop

void loop() 
{
	serial_commands_.ReadSerial();
}

Multiple Serial Ports

#include <SerialCommands.h>

char serial_commands_0_buffer_[32];
SerialCommands serial_commands_0_(&Serial, serial_commands_0_buffer_, sizeof(serial_commands_0_buffer_));

char serial_commands_1_buffer_[32];
SerialCommands serial_commands_1_(&Serial1, serial_commands_1_buffer_, sizeof(serial_commands_1_buffer_));

void cmd_hello(SerialCommands* sender)
{
	sender->GetSerial()->println("HELLO from arduino!");
}

void cmd_unrecognized(SerialCommands* sender, const char* cmd)
{
	sender->GetSerial()->print("ERROR: Unrecognized command [");
	sender->GetSerial()->print(cmd);
	sender->GetSerial()->println("]");
}

SerialCommand cmd_hello_0_("hello", cmd_hello);
SerialCommand cmd_hello_1_("hello", cmd_hello);

void setup() 
{
    Serial.begin(57600);
	serial_commands_0_.AddCommand(&cmd_hello_0_);
	serial_commands_0_.SetDefaultHandler(&cmd_hello);
	
    Serial1.begin(57600);
	serial_commands_1_.AddCommand(&cmd_hello_1_);
	serial_commands_1_.SetDefaultHandler(&cmd_hello);
}

void loop() 
{
	serial_commands_0_.ReadSerial();
	serial_commands_1_.ReadSerial();
}