morse.pde

/***
	morse.pde: Morse code input/output codec for Bitlash

	Bitlash is a tiny language interpreter that provides a serial port shell environment
	for bit banging and hardware hacking.

	Bitlash lives at: http://bitlash.net
	The author can be reached at: bill@bitlash.net

	Copyright (C) 2008-2012 Bill Roy

	Permission is hereby granted, free of charge, to any person
	obtaining a copy of this software and associated documentation
	files (the "Software"), to deal in the Software without
	restriction, including without limitation the rights to use,
	copy, modify, merge, publish, distribute, sublicense, and/or sell
	copies of the Software, and to permit persons to whom the
	Software is furnished to do so, subject to the following
	conditions:
	
	The above copyright notice and this permission notice shall be
	included in all copies or substantial portions of the Software.
	
	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
	OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
	HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
	WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	OTHER DEALINGS IN THE SOFTWARE.
***/

/****************

Bitlash morse code example

This example adds morse code output to Bitlash.

There are three new functions:

The function printm() is the main action.  It acts like printf(), but the output
is signalled in morse code on the pins defined below in the configuration section.

Both a positive-going steady-on and a tone output are supported.  
	- connect an LED/resistor to the steady-on output
	- connect a piezo buzzer/resistor to the tone output

The frequency of the tone is adjustable using the freq() function (default 800 Hz)

The morse code transmission speed is adjustable using the wpm() function (default 15 wpm) 

A push-to-talk signal is supported, with a configurable keyup delay (default 10ms)

Morse output is blocking.  In this implementation, everything freezes in delay()
while morse is being sent.  It is not ideal.  A little state machine and buffer 
could take care of that.

Example: Send callsign in CW every ten minutes

	function beacon {printm("W1AW");}
	run beacon,10*60*1000
	
Example: Send temperature report in morse code every minute

	function get_temp {...however you get the temperature...}
	function temp_report {printm("temp: %d %u", get_temp(), millis);}
	run temp_report,60*1000

Project: Make a QRP beacon with an oscillator-in-a-can on the ham bands
	- PTT provides/switches power
	- signal using the steady-on output

TODO: print prosigns BK SK AR correctly

****************/
#include "bitlash.h"


// CONFIGURATION

// Pin Assignments
#define PIN_PTT		3	// push to talk output: any digital pin
#define PIN_TX		4	// continuous output: any digital pin
#define PIN_TONE	5	// tone output: any PWM pin (for tone())

#define DEFAULT_WPM 15			// morse speed in PARIS words per minute
#define DEFAULT_SIDETONE 800	// tone frequency in Hz
#define PTT_DELAY	10			// ms to delay before sending after pulling PTT high

// END CONFIGURATION



/////////////////////////////////
//
// MORSE OUTPUT
//

//////////
// The Morsetab
//
// Each value in the table is bit-encoded as lllddddd, where:
//	lll is 3 bits of length [0..7] and 
//	ddddd is 5 bits of morse data, 1==dah and 0==dit
// since there are only 5 bits for morse data we handle 6 element symbols as a special case
// they are stored with a length of zero and an index into 'm6codes', an exception array below
//
#define m(a,b) ((a<<5) + b)
#define m6(b) m(0,b)
#define NIL m(6,0xc)
#include "avr/pgmspace.h"
const prog_char morsetab[] PROGMEM = {
	//2 SP      !      "      #    $       %    &        '          (         )      *    +         ,      -      .          slash
		NIL, m6(2), m6(6), NIL, m(7,9), NIL, m(5,8), m(6,0x1e), m(5,0x16), m6(3), NIL, m(5,0xa), m6(4), m6(5), m(6,0x15), m(5,0x12),
	//3   0   		1   		2   	3   	4   		5   	6   	7   		8   		9   	 :  	;  		<    =   	   >    ?
		m(5,0x1f), m(5,0x0f), m(5,7), m(5,3), m(5,1), m(5,0), m(5,0x10), m(5,0x18), m(5,0x1c), m(5,0x1e), m6(0), m6(1), NIL, m(5,0x11), NIL, m(6,0xc),
	//4	@       	a		b		c		d		e		f		g		h			i		j		k		l		m		n		o
		m(6,0x1a), m(2,1), m(4,8), m(4,0xa), m(3,4), m(1,0), m(4,2), m(3,6), m(4,0), m(2,0), m(4,7), m(3,5), m(4,4), m(2,3), m(2,2), m(3,7),
	//5  P   	Q   		R   	S   	T   	U   	V   	W   	X   	Y   		Z     [    \          ]    ^    _
		m(4,6), m(4,0xd), m(3,2), m(3,0), m(1,1), m(3,1), m(4,1), m(3,3), m(4,9), m(4,0xb), m(4,0xc), NIL, m(5,0x12), NIL, NIL, m(6,0xd)
};

/*
$ m(7,9)
*/

#define NUM_SPECIAL_CHARS 13
//                              012345 6789012
const prog_char outliers[] PROGMEM = ":;!),-\"'.?@_#";

const char m6codes[NUM_SPECIAL_CHARS] PROGMEM = {
//	0=:  1=;  2=!  3=)  4=,  5=-  6="  7='  8=.  9=?  10=@ 11=_ 12=SK/#
	0x38,0x2a,0x2b,0x2d,0x33,0x21,0x12,0x1e,0x15,0x0c,0x1a,0x0d,0x05
};

numvar morse_dit_ms;
numvar morse_dah_ms;
numvar sidetone_freq;

void send_morse_element(int dt) {
	digitalWrite(PIN_TX, 1);
	tone(PIN_TONE, sidetone_freq);
	delay(dt);

	noTone(PIN_TONE);
	digitalWrite(PIN_TX, 0);
	delay(morse_dit_ms);		// symbolspace of silence
}

void sendMorseElementPattern(byte bitcount, byte data) {
	byte mask = 1 << (bitcount-1);
	while (mask) {
		send_morse_element( (data & mask) ? morse_dah_ms : morse_dit_ms );
		mask >>= 1;
	}
	delay(2 * morse_dit_ms);	// letterspace less symbolspace taken above
}

void sendMorseChar(byte c) {
	if (c == ' ') { delay(6 * morse_dit_ms); return; }		// wordspace
	if ((c >= 'a') && (c <= 'z')) c = c - 'a' + 'A';
	if ((c < ' ') || (c > '_')) return;    // ignore bogus 7-bit and all 8-bit
	byte tablecode = pgm_read_byte(morsetab + c - ' ');
	byte len = (tablecode >> 5) & 7;
	if (len) sendMorseElementPattern(len, tablecode & 0x1f);
	else sendMorseElementPattern(6, pgm_read_byte(m6codes + tablecode));
}

void sendMorseString(char *str) {while (*str) sendMorseChar(*str++); }

void initMorse(void) {
	setwpm(DEFAULT_WPM);
	sidetone_freq = DEFAULT_SIDETONE;
}


///////////////////
//
// Bitlash API
//


//////////
//
// printm(): printf in morse code
//
numvar func_printm(void) {

	// light up the push-to-talk pin
	digitalWrite(PIN_PTT, HIGH);
	if (PTT_DELAY) delay(PTT_DELAY);

	// route Bitlash output to the morse generator
	setOutputHandler(&sendMorseChar);

	// do the print-to-morse
	extern numvar func_printf_handler(byte, byte);
	func_printf_handler(1,2);	// format=arg(1), optional args start at 2

	// restore normal output
	resetOutputHandler();

	// drop PTT
	digitalWrite(PIN_PTT, LOW);
	return 0;
}


//////////
//
// setwpm(): set words-per-minute
//
numvar func_wpm(void) {
	setwpm(getarg(1));
	return 0;
}

void setwpm(unsigned int wpm) {
	if ((wpm == 0) || (wpm > 1200)) wpm = DEFAULT_SIDETONE;
	morse_dit_ms = (1200 / wpm);
	morse_dah_ms = (3 * (1200 / wpm));
}


//////////
//
// setfreq(): set sidetone frequency
//
numvar func_freq(void) {
	if (getarg(0)) sidetone_freq = getarg(0);
	return 0;
}


//////////////////////////
//
// Example main program
//
void setup(void) {

	// init output pins
	pinMode(PIN_PTT, OUTPUT); digitalWrite(PIN_PTT, LOW);
	pinMode(PIN_TX, OUTPUT); digitalWrite(PIN_TX, LOW);
	pinMode(PIN_TONE, OUTPUT); digitalWrite(PIN_TONE, LOW);

	// init morse subsystem
	initMorse();

	// register our function extensions
	addBitlashFunction("printm", (bitlash_function) func_printm);
	addBitlashFunction("wpm", (bitlash_function) func_wpm);
	addBitlashFunction("freq", (bitlash_function) func_freq);

	// init bitlash last so it can send morse from the startup function
	initBitlash(57600);
}

void loop(void) {
	runBitlash();
}