apple1-videocard-lib/demos/viatimer/viatimer.c
2022-02-22 14:15:30 +01:00

113 lines
2.6 KiB
C

#define APPLE1_USE_WOZ_MONITOR 1
//#pragma start_address(0x8000)
//#pragma start_address(0x0280)
#include <string.h>
#include <utils.h>
#include <apple1.h>
#include <via.h>
#include <interrupt.h>
const word ONE_TICK = 16666; // timer constant for 1/60 second
byte last_sec = 0xFF;
void print_clock() {
if(last_sec != _seconds) {
last_sec = _seconds;
woz_print_hex(_hours); woz_putc('.');
woz_print_hex(_minutes); woz_putc('.');
woz_print_hex(_seconds); woz_putc('\r');
}
}
// same routine as interrupt handler, but does not use RTI
void time_count() {
// update the watch
if(++_ticks == 60) {
_ticks = 0;
if(++_seconds == 60) {
_seconds = 0;
if(++_minutes == 60) {
_minutes = 0;
_hours++;
}
}
}
_irq_trigger = 1; // signals that an interrupt has been triggered
#ifdef VIA6522
VIA_ACK_INTERRUPT;
#endif
}
void test_timer_poll() {
woz_puts("*** TIMER IN POLL MODE ***\r\rPRESS X TO EXIT\r\r");
*VIA_IER = 0; // disable T1 interrupts (poll mode)
*VIA_ACR = 0b01000000; // timer 1 generates continuous interrupts
*VIA_T1CL = BYTE0(ONE_TICK); // programs the counter to 1/60
*VIA_T1CH = BYTE1(ONE_TICK); // and starts counting
while(1)
{
// wait until IFR bit 6 is set by the counter reaching zero
while(!(*VIA_IFR & VIA_IFR_MASK_T1));
// do the time counting as if it was a normal iterrupt
time_count();
print_clock();
if(apple1_readkey()=='X') break;
}
*VIA_ACR = 0; // stop T1 (makes it one-shot)
}
void test_timer_interrupt() {
woz_puts("*** TIMER IN INTERRUPT MODE ***\r\rPRESS X TO EXIT\r\r");
// install the interrupt handler
install_interrupt((word) &time_interrupt_handler);
*VIA_IER = 0b11000000; // enable T1 interrupts
*VIA_ACR = 0b01000000; // T1 continous, PB7 disabled
*VIA_T1CL = BYTE0(ONE_TICK); // programs the counter to 1/60
*VIA_T1CH = BYTE1(ONE_TICK); // and starts counting
while(1)
{
print_clock();
if(apple1_readkey()=='X') break;
}
*VIA_IER = 0b01000000; // disable T1 interrupts
*VIA_ACR = 0; // stop T1 (makes it one-shot)
}
void main() {
woz_puts("\rTESTING THE VIA 6522\r");
while(1) {
woz_puts("\r"
"P - POLL MODE\r"
"I - INTERRUPT MODE\r"
"X - EXIT\r\r"
);
byte k = apple1_getkey();
if(k=='P') test_timer_poll();
else if(k=='I') test_timer_interrupt();
else if(k=='X') break;
}
woz_puts("BYE!\r");
woz_mon();
}