BattClock Resource

This page is currently being updated to AmigaOS 4.x. Some of the information contained here may not yet be applicable in part or totally.

The battery-backed clock (BattClock) keeps Amiga time while the system is powered off. The time from the BattClock is loaded into the Amiga system clock as part of the boot sequence.

The battclock resource provides access to the BattClock. Three functions allow you to read the BattClock value, reset it and set it to a value you desire.

BattClock Resource Functions

ReadBattClock()	Read the time from the BattClock and returns it as the number of seconds since 12:00 AM, January 1, 1978.
ResetBattClock()	Reset the BattClock to 12:00 AM, January 1, 1978.
WriteBattClock()	Set the BattClock to the number of seconds you pass it relative to 12:00 AM, January 1, 1978.

The utility.library contains time functions which convert the number of seconds since 12:00 AM, January 1, 1978 to a date and time we can understand, and vice versa. You will find these functions useful when dealing with the BattClock. The example program below uses the Amiga2Date() utility function to convert the value returned by ReadBattClock(). See the Utility Library for a discussion of the utility.library and the SDK for a listing of its functions.

So, You Want to Be A Time Lord?
This resource will allow you to set the BattClock to any value you desire. Keep in mind that this time will endure a reboot and could adversely affect your system.

/*
 * Read_BattClock.c
 *
 * Example of reading the BattClock and converting its output to
 * a useful measure of time by calling the Amiga2Date() utility function.
 *
 * Compile with SAS C 5.10  lc -b1 -cfistq -v -y -L
 *
 * Run from CLI only
 */

#include <exec/types.h>
#include <dos/dos.h>
#include <utility/date.h>
#include <resources/battclock.h>

#include <clib/exec_protos.h>
#include <clib/alib_protos.h>
#include <clib/battclock_protos.h>
#include <clib/utility_protos.h>

#include <stdio.h>

#ifdef LATTICE
int CXBRK(void) { return(0); }  /* Disable SAS CTRL/C handling */
int chkabort(void) { return(0); }  /* really */
#endif

VOID main(VOID);

struct Library *UtilityBase = NULL;
struct Library *BattClockBase;

VOID main(VOID)
{
UBYTE *Days[] ={"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"};
UBYTE *Months[] = {"January","February","March","April","May","June",
                   "July","August","September","October","November","December"};
UBYTE *ampm;
ULONG AmigaTime;
struct ClockData MyClock;

if (UtilityBase = (struct Library *)OpenLibrary("utility.library",33))
    {
    if (BattClockBase= OpenResource(BATTCLOCKNAME))
        {
        /* Get number of seconds till now */
        AmigaTime = ReadBattClock();

        /* Convert to a ClockData structure */
        Amiga2Date(AmigaTime,&MyClock);

        printf("\nRobin, tell everyone the BatDate and BatTime");

        /* Print the Date */
        printf("\n\nOkay Batman, the BatDate is ");
        printf("%s, %s %d, %d",Days[MyClock.wday],Months[MyClock.month-1],
                               MyClock.mday,MyClock.year);

        /* Convert military time to normal time and set AM/PM */
        if (MyClock.hour < 12)
            ampm = "AM";        /* hour less than 12, must be morning */
        else
            {
            ampm = "PM";         /* hour greater than 12,must be night */
            MyClock.hour -= 12;  /* subtract the extra 12 of military */
            };

        if (MyClock.hour == 0)
            MyClock.hour = 12;   /* don't forget the 12s */

        /* Print the time */
        printf("\n             the BatTime is ");
        printf("%d:%02d:%02d %s\n\n",MyClock.hour,MyClock.min,MyClock.sec,ampm);
        }
    else
       printf("Error: Unable to open the %s\n",BATTCLOCKNAME);

    /* Close the utility library */
    CloseLibrary(UtilityBase);
    }

else
    printf("Error: Unable to open utility.library\n");
}

Additional programming information on the battclock resource can be found in the include files and the Autodocs for the battclock resource and the utility library.