The Apple III clock is accessible from machine language under CP/M. There
are two call addresses in BIOS used to read and set the clock. Both use a
common 18 byte area for returning the Date/Time or for setting the clock.
If no clock is installed, the byte at 0DFE0H is 00H.
To Set Clock: Call 0DF89H
To Read Clock: Call 0DF86H
Example: Friday, March 21, 1982, 1:27 PM and 41.234 seconds is represented
as the ASCII string: "198203216132741234".
Addresses Contents
Hex ASCII
Year: 0DFE0H 31 (1)
0DFE1H 39 (9)
0DFE2H 38 (8)
0DFE3H 32 (2)
Month: 0DFE4H 30 (0)
0DFE5H 33 (3)
Day: 0DFE6H 32 (2)
0DFE7H 31 (1)
Day of week: 0DFE8H 36 (6) (1=Sunday)
Hour: 0DFE9H 31 (1)
0DFEAH 33 (3)
Minute: 0DFEBH 32 (2)
0DFECH 37 (7)
Second: 0DFEDH 34 (4)
0DFEEH 31 (1)
Tenths: 0DFEFH 32 (2)
Hundrenths: 0DFF0H 33 (3)
Thousands: 0DFF1H 34 (4)