borgware-2d/borg_hw/borg_hw_gigaborg.c

#include "../config.h"
#include "../makros.h"

#include <avr/interrupt.h>
#include <avr/io.h>
#include <avr/wdt.h>
#include "borg_hw.h"

/*
 // those macros get defined via menuconfig, now

 // 16 columns total directly controlled, therefore 2 ports
 #define COLPORT1  PORTC
 #define COLDDR1   DDRC

 #define COLPORT2  PORTA
 #define COLDDR2   DDRA

 // the other port controls the shift registers
 #define ROWPORT   PORTD
 #define ROWDDR    DDRD

 // both clock and reset are connected to each shift register
 // reset pin is negated
 #define PIN_MCLR  PD4
 #define PIN_CLK   PD6

 // these are the individual data input pins for the shift registers
 #define PIN_DATA  PD7
*/

#define COLDDR1  DDR(COLPORT1)
#define COLDDR2  DDR(COLPORT2)
#define ROWDDR   DDR(ROWPORT)

#if defined (__AVR_ATmega644P__) || defined (__AVR_ATmega644__) || (__AVR_ATmega1284P__) || defined (__AVR_ATmega1284__)
/* more ifdef magic :-( */
#define OCR0 OCR0A
#define TIMER0_COMP_vect TIMER0_COMPA_vect
#endif


// buffer which holds the currently shown frame
unsigned char pixmap[NUMPLANE][NUM_ROWS][LINEBYTES];


// depending on the plane this interrupt gets triggered at 50 kHz, 31.25 kHz or
// 12.5 kHz
ISR(TIMER0_COMP_vect) {
	// reset watchdog
	wdt_reset();

	COLPORT1 = (pixmap[0][0][0] & 0x0f) | (pixmap[0][1][0] << 4);
	COLPORT2 = (pixmap[0][2][0] & 0x0f) | (pixmap[0][3][0] << 4);
}


void timer0_off() {
	cli();

	COLPORT1 = 0;
	COLPORT2 = 0;
	ROWPORT = 0;

#if defined (__AVR_ATmega644P__) || defined (__AVR_ATmega644__) || (__AVR_ATmega1284P__) || defined (__AVR_ATmega1284__)
	TCCR0A = 0x00;
	TCCR0B = 0x00;
#else
	TCCR0 = 0x00;
#endif
	sei();
}


// initialize timer which triggers the interrupt
void timer0_on() {
	/* 	TCCR0: FOC0 WGM00 COM01 COM00 WGM01 CS02 CS01 CS00
	 CS02 CS01 CS00
	 0    0    0       stop
	 0    0    1       clk
	 0    1    0       clk/8
	 0    1    1       clk/64
	 1    0    0       clk/256
	 1    0    1       clk/1024
	 */
#if defined (__AVR_ATmega644P__) || defined (__AVR_ATmega644__) || (__AVR_ATmega1284P__) || defined (__AVR_ATmega1284__)
	TCCR0A = 0x02; // CTC Mode
	TCCR0B = 0x04; // clk/256
	TCNT0  = 0;    // reset timer
	OCR0   = 20;   // compare with this value
	TIMSK0 = 0x02; // compare match Interrupt on
#else
	TCCR0  = 0x0C; // CTC Mode, clk/256
	TCNT0  = 0;    // reset timer
	OCR0   = 20;   // compare with this value
	TIMSK  = 0x02; // compare match Interrupt on
#endif
}


void borg_hw_init() {
	// switch column ports to output mode
	COLDDR1 = 0xFF;
	COLDDR2 = 0xFF;

	// switch pins of the row port to output mode
	ROWDDR = (1 << PIN_MCLR) | (1 << PIN_CLK) | (1 << PIN_DATA);

	// switch off all columns for now
	COLPORT1 = 0;
	COLPORT2 = 0;

	// reset shift registers for the rows
	ROWPORT = 0;

	// switch on all row output ports of the gigaborg
	ROWPORT |= (1 << PIN_DATA) | (1 << PIN_MCLR);
	uint8_t x;
	for (x = 0; x < 16; x++) {
		ROWPORT |= (1 << PIN_CLK);
		ROWPORT &= ~(1 << PIN_CLK);
	}

	timer0_on();

	// activate watchdog timer
	wdt_reset();
	wdt_enable(0x00); // 17ms watchdog
}