Nagasaki PC104-688VL, User Manual

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NAGASAKI IPC
52
Technical Reference
Real-Time Clock and Non-Volatile RAM
The PC104-688VL contains a real-time clock compartment that maintains the date and
time in addition to storing configuration information about the computer system. It
contains 14 bytes of clock and control registers and 114 bytes of general purpose RAM.
Because of the use of CMOS technology, it consumes very little power and can be
maintained for long periods of time using an internal Lithium battery. The contents of
each byte in the CMOS RAM are listed below:
Address Description
00 Seconds
01 Second alarm
02 Minutes
03 Minute alarm
04 Hours
05 Hour alarm
06 Day of week
07 Date of month
08 Month
09 Year
0A Status register A
0B Status register B
0C Status register C
0D Status register D
0E Diagnostic status byte
0F Shutdown status byte
10 Diskette drive type byte, drive A and B
11 Fixed disk type byte, drive C
12 Fixed disk type byte, drive D
13 Reserved
14 Equipment byte
15 Low base memory byte
16 High base memory byte