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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"
#define PIN_DATA PB4
#define PIN_CLK PB3
#define PIN_STR PB2
// buffer which holds the currently shown frame
unsigned char pixmap[NUMPLANE][NUM_ROWS][LINEBYTES];
// switch to next row
static void nextrow(uint8_t row) {
// clear states of the preceding row
PORTC &= 0xF0;
PORTD &= 0x0F;
PORTB &= 0xFC;
// short delay loop, to ensure proper deactivation of the drivers
unsigned char i;
for (i = 0; i < 10; i++) {
asm volatile("nop");
}
if (row == 0) {
// row 0: initialize first shift register
PORTB &= ~(1 << PIN_DATA); // row is active low
PORTB |= (1 << PIN_CLK);
PORTB &= ~(1 << PIN_CLK);
PORTB |= (1 << PIN_DATA);
} else {
// remaining rows: just shift forward
PORTB |= (1 << PIN_CLK);
PORTB &= ~(1 << PIN_CLK);
}
// another delay loop, to ensure that the drivers are ready
for (i = 0; i < 20; i++) {
asm volatile("nop");
}
}
// display a row
static void rowshow(unsigned char row, unsigned char plane) {
// depending on the currently drawn plane, display the row for a specific
// amount of time
static unsigned char const tcnt0_table[] = {244, 236, 206};
TCNT0 = tcnt0_table[plane];
// output data of the current row to the column drivers
uint8_t tmp, tmp1;
tmp = pixmap[plane][row][0];
tmp1 = pixmap[plane][row][1];
PORTC = (PORTC & 0xF0) | (tmp & 0x0F);
PORTD = (PORTD & 0x0F) | (tmp & 0xF0);
PORTB = (PORTB & 0xFC) | (tmp1 & 0x03);
}
// depending on the plane this interrupt gets triggered at 50 kHz, 31.25 kHz or
// 12.5 kHz
ISR(TIMER0_OVF_vect) {
static unsigned char plane = 0;
static unsigned char row = 0;
// reset watchdog
wdt_reset();
// increment both row and plane
if (++plane == NUMPLANE) {
plane = 0;
if (++row == NUM_ROWS) {
row = 0;
}
nextrow(row);
}
// output current row according to current plane
rowshow(row, plane);
}
void timer0_off() {
cli();
/*
COLPORT1 = 0;
COLPORT2 = 0;
ROWPORT = 0;
*/
TCCR0 = 0x00;
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
*/
TCCR0 = 0x03; // clk/64
TCNT0 = 0xFF - 20; // reset timer
TIMSK |= (1 << TOIE0); // compare match Interrupt on
}
void borg_hw_init() {
// set required pins to output mode
DDRC = 0x0F; // PC0-3 - Row 0-3
DDRD = 0xF4; // PD4-7 - Row 4-7 PD2 - ground for joy
DDRB = 0x1F; // PB0-1 - Row 8-9 PB2-3 - STR, CLK, d
// turn off all columns for now, clk off, d and str on
// PC4-5, PD013 pullup on
PORTC = 0x30;
PORTD = 0x0B;
PORTB = 0x14;
timer0_on();
// activate watchdog timer
wdt_reset();
wdt_enable(0x00); // 17ms watchdog
}