Sample program using the STOP instruction for low power mode with the 68HC11

#include <hc11.h>
#include "pia.h"
#include "rtc.h"
#include "spi.h"

#define TRUE 1


void irq_isr(void);

struct rtc_regs rtc;
unsigned char time[10000];
unsigned int time_index;

main()
{
	time_index = 0;

	setup_spi(SPI_ENABLE | SPI_MASTER | SPI_CPOL_ZERO | SPI_CPHASE_ONE
			| SPI_CLOCK_E_DIV2);

	/* Set the RTC to the current time */
	setup_rtc();

	/* The following instructions clear the STOP bit of the CCR */
	asm(" tpa");
	asm(" anda 0x7f");
	asm(" tap");

	enable();

	while (TRUE)
	{
		asm(" stop");
	}
}

void irq_isr(void)
/* In ISR, read the time from the clock and save in data array;
 * read_rtc() resets interrupt flip flop when Slave Select (Port D Bit 5) 
 * goes high
 */
{
	read_rtc(&rtc);
	time[time_index++]=rtc.year;
	time[time_index++]=rtc.month;
	time[time_index++]=rtc.dom;
	time[time_index++]=rtc.hour;
	time[time_index++]=rtc.min;
	time[time_index++]=rtc.sec;
}