midi-footswitch/firmware/midifs.c

// midifs.c
// Typ: C-Sourcerfile
// Project: MIDI Footswitch
// Date: 17.06.2014
// Author: ska

#define F_CPU 8000000UL

#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include "midifs.h"
#include "usart.h"

volatile unsigned char status_channel, status, channel, data1, data2;
volatile unsigned int iBtn1_counter = 0, iBtn2_counter = 0, iBtn3_counter = 0, iBtn4_counter = 0, iSw1_counter = 0, iSw2_counter = 0;
volatile unsigned char cBtn1 = 0, cBtn2 = 0, cBtn3 = 0, cBtn4 = 0, cSw1 = 0, cSw2 = 0;
volatile unsigned char cChannel = 0, cBank = 0; cTuner = 0;
unsigned int cnt = 0;

int main (void)
{
	DDRB = 0x00;				// PB1..7 as inputs
	PORTB = 0xFF;				// interlan pull-ups for PB0..7y
	DDRD = 0x30;				// PD4..5 as outputs
	PORTD = 0x0C;				// internal pull-ups for PD2..3

	OUT_LED = 0x30;				// LEDs off

	//	Timer1 init
	TCCR1A |= (1 << WGM01);			//	set timer 0 to CTC-Mode
	TCCR1B &= ~(1 << CS10);			//	prescaler 8  (1MHz)
	TCCR1B |= (1 << CS11);
	TCCR1B &= ~(1 << CS12);
	OCR1A = 499;				//	period of 1 ms

	cli();					// disable interrupts
	TIMSK |= (1 << TOIE1);			// activate timer 1
	sei();					//  enable interrupts

	//USART_Init(38400);			// initialize USART with 38400 baud (debug)
	USART_Init(31250);			// initialize USART with 31250 baud

	while (1) {
		if (iBtn1_counter > BTN_THRESHOLD && cBtn1 == 0)		// Button 1
		{
			Bank(cBank);
			USART_Transmit(0xC0);	// Channel 1
			USART_Transmit(0x00);

			cChannel = 0;
			cTuner = 0;

			cBtn1 = 1;
		}
		else if (iBtn1_counter < BTN_THRESHOLD && cBtn1 == 1)
			cBtn1 = 0;

		if(iBtn2_counter > BTN_THRESHOLD && cBtn2 == 0)			// Button 2
		{
			Bank(cBank);
			USART_Transmit(0xC0);	// Channel 2
			USART_Transmit(0x01);
			cChannel = 1;
			cTuner = 0;

			cBtn2 = 1;
		}
		else if (iBtn2_counter < BTN_THRESHOLD && cBtn2 == 1)
			cBtn2 = 0;

		if(iBtn3_counter > BTN_THRESHOLD && cBtn3 == 0)			// Button 3
		{
			Bank(cBank);
			USART_Transmit(0xC0);	// Channel 3
			USART_Transmit(0x02);
			cChannel = 2;
			cTuner = 0;

			cBtn3 = 1;
		}
		else if (iBtn3_counter < BTN_THRESHOLD && cBtn3 == 1)
			cBtn3 = 0;

		if(iBtn4_counter > BTN_THRESHOLD && cBtn4 == 0)			// Button 4
		{
			USART_Transmit(0xB0);	// Tuner on
			USART_Transmit(0x0F);
			USART_Transmit(0x7F);

			//OUT_LED |= (1 << LED_RT);	// LEDs off
			//OUT_LED |= (1 << LED_GN);

			cTuner = 1;

			cBtn4 = 1;
		}
		else if (iBtn4_counter < BTN_THRESHOLD && cBtn4 == 1)
			cBtn4 = 0;

		if (iSw1_counter > BTN_THRESHOLD && cSw1 == 0)			// Switch Pos. 1
		{
			Bank(0);
			cBank = 0;
			cTuner = 0;

			cSw1 = 1;
		}
		else if (iSw1_counter < BTN_THRESHOLD && cSw1 == 1)
		{
			cSw1 = 0;
		}

		if(iSw2_counter > BTN_THRESHOLD && cSw2 == 0)			// Switch Pos. 2
		{
			Bank(1);
			cBank = 1;
			cTuner = 0;

			cSw2 = 1;
		}
		else if (iSw2_counter < BTN_THRESHOLD && cSw2 == 1)
		{
			cSw2 = 0;
		}

	}
}

void Bank(unsigned char num) {
	if(num == 0) {
		USART_Transmit(0xB0);		// Bank 1
		USART_Transmit(0x00);
		USART_Transmit(0x00);
		USART_Transmit(0xC0);
		USART_Transmit(0x00);
		USART_Transmit(cChannel);
		OUT_LED &= ~(1 << LED_RT);	// LED green
		OUT_LED |= (1 << LED_GN);
	}
	else {
		USART_Transmit(0xB0);		// Bank 2
		USART_Transmit(0x00);
		USART_Transmit(0x01);
		USART_Transmit(0xC0);
		USART_Transmit(0x00);
		USART_Transmit(cChannel);
		OUT_LED &= ~(1 << LED_GN);	// LED green
		OUT_LED |= (1 << LED_RT);
	}
}

/* interrupt function:	TIMER1_OVF1_vect
 *
 * Timer interrupt. Increments counters for inputs
 */
ISR(TIMER1_OVF_vect)
{
	if(++cnt == 250) cnt = 0;
	if(cTuner == 1 && cnt == 1) {
		if(cBank == 1) OUT_LED ^= (1<<LED_GN);
		else OUT_LED ^= (1<<LED_RT);
	}

	if (bit_is_clear(IN_BTN, BTN1)) {					// Button 1
		if (iBtn1_counter < BTN_MAX) iBtn1_counter++;
	} else {
		if (iBtn1_counter > 0) iBtn1_counter--;
	}
	if (bit_is_clear(IN_BTN, BTN2)) {					// Button 2
		if (iBtn2_counter < BTN_MAX) iBtn2_counter++;
	} else {
		if (iBtn2_counter > 0) iBtn2_counter--;
	}
	if (bit_is_clear(IN_BTN, BTN3)) {					// Button 3
		if (iBtn3_counter < BTN_MAX) iBtn3_counter++;
	} else {
		if (iBtn3_counter > 0) iBtn3_counter--;
	}
	if (bit_is_clear(IN_BTN, BTN4)) {					// Button 4
		if (iBtn4_counter < BTN_MAX) iBtn4_counter++;
	} else {
		if (iBtn4_counter > 0) iBtn4_counter--;
	}
	if (bit_is_clear(IN_SW, SW1)) {						// Switch 1
		if (iSw1_counter < BTN_MAX) iSw1_counter++;
	} else {
		if (iSw1_counter > 0) iSw1_counter--;
	}
	if (bit_is_clear(IN_SW, SW2)) {						// Switch 2
		if (iSw2_counter < BTN_MAX) iSw2_counter++;
	} else {
		if (iSw2_counter > 0) iSw2_counter--;
	}
}