/*

	Title:		CV test signal generator
	Author:		Satoshi "Chuck" Takagi
	Date:		Jan., 02, 2006
				Jul., 22, 2006
	Software:	WinAvr
	Target:		ATtiny2313
*/

#include <inttypes.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/signal.h>

#define SW_SEL PB7
#define SW_OCT1 PB6
#define SW_OCT2 PB5

volatile struct {
	uint8_t cmd;
	uint8_t stat;
	uint8_t filt;
} gCntl;

SIGNAL(SIG_TIMER0_OVF)
{
	uint8_t a, b;

	TCNT0 = 256 - 125;

	a = ~PINB & (_BV(SW_SEL)|_BV(SW_OCT1)|_BV(SW_OCT2));
	if (a == gCntl.filt) {
		b = gCntl.stat;
		gCntl.stat = a;
		b = (b ^ a) & a;
		if (b) {
			gCntl.cmd = b;
		}
	}
	gCntl.filt = a;
}

void init_io(void)
{
	DDRD = 0xff;		// Port D output for LED
	PORTD = 0;

	DDRB = 0x1F;		// Port B PB765 input for SW, PB2 output for OC0A
	PORTB = 0xE0;

	// timer0
	TCCR0A = 0x00;	// for timer1 setting
	TCCR0B = 0x03;	// CS1[2:0] = 011b clk/64
	TCNT0 = 256 - 125;
	TIMSK = (1<<TOIE0);	// timer1 interrupt enabled

	// PWM
	TCCR1A = (1<<COM1A1)|(1<<COM1A0)|(1<<WGM11);
		// 0xC2(0110xx11) : COM0A=11b, COM0B[1:0] = 00b, WGM0[1:0] = 2'b10 FastPWM 9-bit
	TCCR1B = (1<<WGM12)|(1<<CS10);	// WGM0[3:2] = 01b, CS0[2:0] = 001

}


int main(void)
{
	uint8_t ptr = 0;

	struct {
		uint16_t pwm;
		uint8_t led;
	} tbl[] = {
		{ 511 -   0    , 0x00 },
		{ 511 - 100 + 0, 0x01 },
		{ 511 - 200 + 1, 0x03 },
		{ 511 - 300 + 1, 0x07 },
		{ 511 - 400 + 1, 0x0f },
		{ 511 - 500, 0x1f },
		{ 511 - 511, 0x1f },
		{ 511 - 511, 0x1f }
	};


	init_io();
	sei();		/* enable interrupts     */

	while(1) {

		if ( gCntl.cmd & _BV(SW_SEL) ) {
			if (++ptr > 5)	ptr = 0;
			OCR1A = tbl[ptr].pwm;
			PORTD = tbl[ptr].led;
			gCntl.cmd = 0;
		} else if ( gCntl.stat & _BV(SW_OCT1) ) {
			OCR1A = tbl[ptr + 1].pwm;
			PORTD = tbl[ptr + 1].led;
			gCntl.cmd = 0;
		} else if ( gCntl.stat & _BV(SW_OCT2) ) {
			OCR1A = tbl[ptr + 2].pwm;
			PORTD = tbl[ptr + 2].led;
			gCntl.cmd = 0;
		} else {
			OCR1A = tbl[ptr].pwm;
			PORTD = tbl[ptr].led;
		}

	}

}