Contains a rechargeable battery, five chips, a quartz crystal, a 8bit general-purpose I/O port (9pin DSUB), and a few odds and ends. The RTC chip is a HD146818 (which is also used in IBM PCs).
Info Fragment
Reportedly: DK-Tronics RTC module used a Z80-PIO chip to address the RTC itself as Port A of the PIO, with a 9-pin user i/o port as Port B.
I/O Ports
FBE0..FBE3 Dk'tronics Real Time Clock FBE8 Dk'tronics Real Time Clock
Software
Included BASIC and CP/M+ drivers:
- RSX.BAS and RSX.BIN - allows to change the time under BASIC
- CLOCK.COM - installs the clock under CP/M+ (thereafter, it should be accessible with standard DATE command, and, it should add timestamps to files).
Unknown how the timestamps are stored on disk? The normal AMSDOS filesystem / directory entries don't include timestamps.
