Technical information

Chapter 2. System Board Features
Real-Time Clock
The real-time clock is a low-power clock that provides a time-of-day clock and a calendar. The clock
settings are maintained by an external battery source of +3 volts.
The system uses 242 bytes of memory to store complementary metal-oxide semiconductor (CMOS)
memory. Moving a jumper (J8) on the system board erases CMOS memory. To locate the battery or J8,
see “System Board” on page 14.
The following table shows the system resources used by the real-time clock.
Note: When the computer is started, the resource assignments are subject to change during the
power-on self-test (POST).
Table 7. System Resource Assignments for the Real-Time Clock
System Resource Assignment
ROM None
RAM None
I/O (hex) 70, 71
IRQ 8
DMA None
12 Technical Information Manual