borgware-2d/borg_hw/borg_hw_andreborg.c

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#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 PORTA
#define COLDDR1 DDRA
#define COLPORT2 PORTC
#define COLDDR2 DDRC
// 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 PD5
// these are the individual data input pins for the shift registers
#define PIN_DATA1 PD6
#define PIN_DATA2 PD7
*/
#define COLDDR1 DDR(COLPORT1)
#define COLDDR2 DDR(COLPORT2)
#define ROWDDR DDR(ROWPORT)
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#ifdef __AVR_ATmega644P__
/* more ifdef magic :-( */
#define OCR0 OCR0A
#define SIG_OUTPUT_COMPARE0 SIG_OUTPUT_COMPARE0A
#endif
// buffer which holds the currently shown frame
unsigned char pixmap[NUMPLANE][NUM_ROWS][LINEBYTES];
// display a row
static void rowshow(unsigned char row, unsigned char plane) {
//reset states of preceding row
COLPORT1 = 0;
COLPORT2 = 0;
// short delay loop, to ensure proper deactivation of the drivers
unsigned char i;
for (i = 0; i < 20; i++) {
asm volatile("nop");
}
if (row == 0) {
// row 0: initialize first shift register
ROWPORT &= ~(1 << PIN_MCLR);
ROWPORT |= (1 << PIN_MCLR);
ROWPORT |= (1 << PIN_DATA1);
ROWPORT |= (1 << PIN_CLK);
ROWPORT &= ~(1 << PIN_CLK);
ROWPORT &= ~(1 << PIN_DATA1);
// depending on the currently drawn plane, display the row for a
// specific amount of time
static unsigned char const ocr0_table[] = {5, 8, 20};
OCR0 = ocr0_table[plane];
} else if (row == 8) {
// row 8: initialize second shift register
ROWPORT &= ~(1 << PIN_MCLR);
ROWPORT |= (1 << PIN_MCLR);
ROWPORT |= (1 << PIN_DATA2);
ROWPORT |= (1 << PIN_CLK);
ROWPORT &= ~(1 << PIN_CLK);
ROWPORT &= ~(1 << PIN_DATA2);
} else {
// remaining rows: just shift forward
ROWPORT |= (1 << PIN_CLK);
ROWPORT &= ~(1 << PIN_CLK);
}
// another delay loop, to ensure that the drivers are ready
for (i = 0; i < 20; i++) {
asm volatile("nop");
}
// output data of the current row to the column drivers
COLPORT1 = pixmap[plane][row][0];
COLPORT2 = pixmap[plane][row][1];
}
// depending on the plane this interrupt gets triggered at 50 kHz, 31.25 kHz or
// 12.5 kHz
SIGNAL(SIG_OUTPUT_COMPARE0) {
static unsigned char plane = 0;
static unsigned char row = 0;
// reset watchdog
wdt_reset();
// output current row according to current plane
rowshow(row, plane);
// increment both row and plane
if (++row == NUM_ROWS) {
row = 0;
if (++plane == NUMPLANE) {
plane = 0;
}
}
}
void timer0_off() {
cli();
COLPORT1 = 0;
COLPORT2 = 0;
ROWPORT = 0;
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#ifdef __AVR_ATmega644P__
TCCR0A = 0x00;
TCCR0B = 0x00;
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#else
TCCR0 = 0x00;
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#endif
sei();
}
// initialize timer which triggers the interrupt
static 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
*/
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#ifdef __AVR_ATmega644P__
TCCR0A = 0x02; // CTC Mode
TCCR0B = 0x03; // clk/64
TCNT0 = 0; // reset timer
OCR0 = 20; // compare with this value
TIMSK0 = 0x02; // compare match Interrupt on
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#else
TCCR0 = 0x0B; // CTC Mode, clk/64
TCNT0 = 0; // reset timer
OCR0 = 20; // compare with this value
TIMSK = 0x02; // compare match Interrupt on
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#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_DATA1) | (1<<PIN_DATA2);
// switch off all columns for now
COLPORT1 = 0;
COLPORT2 = 0;
// reset shift registers for the rows
ROWPORT = 0;
timer0_on();
// activate watchdog timer
wdt_reset();
wdt_enable(0x00); // 17ms watchdog
}