Source

midi / example.c

Full commit
/** \file
 * Iambic USB keyer.
 *
 * Read an iambic keyer on port D and generate key press events
 * based on the Morse code input.
 *
 * (c) 2012 Trammell Hudson <hudson@osresearch.net>
 *
 * Based on the
 * Keyboard example with debug channel, for Teensy USB Development Board
 * http://www.pjrc.com/teensy/usb_keyboard.html
 * Copyright (c) 2008 PJRC.COM, LLC
 * 
 * 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.
 */

#include <avr/io.h>
#include <avr/pgmspace.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include "usb_keyboard_debug.h"
#include "print.h"

#define LED_CONFIG	(DDRD |= (1<<6))
#define CPU_PRESCALE(n)	(CLKPR = 0x80, CLKPR = (n))

static inline void
led_on(void)
{
	PORTD |= (1<<6);
}

static inline void
led_off(void)
{
	PORTD &= ~(1<<6);
}

uint8_t number_keys[10]=
	{KEY_0,KEY_1,KEY_2,KEY_3,KEY_4,KEY_5,KEY_6,KEY_7,KEY_8,KEY_9};

uint16_t idle_count=0;

int main(void)
{
	uint8_t b, d, mask, i, reset_idle;
	uint8_t b_prev=0xFF, d_prev=0xFF;

	// set for 16 MHz clock
	CPU_PRESCALE(0);

	// Configure all port B and port D pins as inputs with pullup resistors.
	// See the "Using I/O Pins" page for details.
	// http://www.pjrc.com/teensy/pins.html
	DDRD = 0x00;
	DDRB = 0x00;
	PORTB = 0xFF;
	PORTD = 0xFF;

	// Initialize the USB, and then wait for the host to set configuration.
	// If the Teensy is powered without a PC connected to the USB port,
	// this will wait forever.
	usb_init();
	while (!usb_configured())
	{
		/* busy wait */
	}

	// Wait an extra second for the PC's operating system to load drivers
	// and do whatever it does to actually be ready for input
	_delay_ms(1000);

	// Timer 0 will be configured to generate an overflow event
	// at the desired code rate.  For dits, 
/*
* http://en.wikipedia.org/wiki/Morse_code#Representation.2C_timing_and_speeds
*
* International Morse code is composed of five elements:
*
* short mark, dot or 'dit' (·) — 'dot duration' is one unit long
* longer mark, dash or 'dah' (–) — three units long
* inter-element gap between the dots and dashes within a character
*   - one dot duration or one unit long
* short gap (between letters) — three units long
* medium gap (between words) — seven units long[19]
*
* Based upon a 50 dot duration standard word such as PARIS, the time
* for one dot duration or one unit can be computed by the formula:
* T = 1200 / W
* or
* T = 6000 / C
* Where: T is the unit time, or dot duration, in milliseconds,
* W is the speed in wpm, and C is the speed in cpm.
*/

#include "morse.h"

	// 
	// 256*1024 clock cycles, or approx 61 Hz when using 16 MHz clock
	// This demonstrates how to use interrupts to implement a simple
	// inactivity timeout.
	TCCR0A = 0x00;
	TCCR0B = 0x05;
	//TIMSK0 = (1<<TOIE0);

	// Hard code at 5 wpm
	const uint16_t dit_time = 240;

	uint8_t value = 1;
	uint8_t bits = 0;
	uint8_t last_bit = 0;

	while (1)
	{
		// Read PINB, which has both input pins
		// since there is a pull-up, the pins will be pulled
		// to ground when the switch is hit.
		const uint8_t pins = PINB;
		const uint8_t dit = (pins & (1 << 5)) ? 0 : 1;
		const uint8_t dah = (pins & (1 << 4)) ? 0 : 1;

		if (bits > 7)
		{
			// Too many symbols.  Ignore it
			print("?\n");
			goto reset;
		} else
		if (dit && (last_bit == 1 || !dah))
		{
			// The dit key is held down and
			// If the last bit sent was also a dit and the
			// dah switch is enabled, send a dah instead.
			last_bit = 0;
			bits++;
			value <<= 1;
			print(".");
			led_on();
			_delay_ms(dit_time);
			led_off();
			_delay_ms(dit_time);
			continue;
		} else
		if (dah)
		{
			last_bit = 1;
			bits++;
			value = (value << 1) | 1;
			print("-");
			led_on();
			_delay_ms(3*dit_time);
			led_off();
			_delay_ms(dit_time);
			continue;
		} else
		if (bits == 0)
		{
#if 0
			if (last_send_time && now() > last_send_time)
				usb_keyboard_press(KEY_SPACE, 0);
			last_send_time = 0;
#endif
			continue;
		}

		// Neither key is held down and the single space time
		// has elapsed (since wait_delay is blocking).

		// Timeout has passed; check to see if the
		// value exist in the map
		uint8_t c = pgm_read_byte(&morse[value]);

		//last_send_time = now();
		print(" = ");
		phex(value);

		if (!c)
		{
			print("!!!\n");
			goto reset;
		}

		print(" ");
		pchar(c);
		pchar('\n');
		
		//usb_keyboard_press(KEY_SPACE, 0);

reset:
		bits = 0;
		value = 1;
	}
}

// This interrupt routine is run approx 61 times per second.
// A very simple inactivity timeout is implemented, where we
// will send a space character and print a message to the
// hid_listen debug message window.
ISR(TIMER0_OVF_vect)
{
	idle_count++;
	if (idle_count > 61 * 8) {
		idle_count = 0;
		print("Timer Event :)\n");
		usb_keyboard_press(KEY_SPACE, 0);
	}
}