Power Fail Interrupt Jumpers (W10, W5) - Xycom XVME-976/202 Manual

Upon power-up or reset, the module jumpered as board number 0 (both
jumpers on) is enabled, allowing the ROM-BIOS or an application program
to detect active memory at that address. For instance, at power-up time, the
ROM-BIOS will scan D0000h for a distinctive bit pattern, (55AAh) and, if
found, execute the program at that address.

Power Fail Interrupt Jumpers (W10, W5)

When the +5V system, (not battery), voltage falls below a trip point (se-
lected by W10) of either 4.75V or 4.5V, on-board circuitry generates a
power fail signal. Table 5-5 shows which jumper pins to short at W10 to
select the trip level.
Jumpers at W5 select which interrupt (if any) to generate when a power fail
signal is received. The power fail interrupt signal can be connected to any of
the IRQ lines on the PC bus or to the -IOCHCK line, which is a non-
maskable interrupt (NMI). Table 4-6 shows which pins to short to select a
particular interrupt. The power fail signal remains active until the voltage
level returns to a normal value (above the trip level).
Remember that the XVME PC/AT will reset when the VMEbus power dips
to 4.85. However, the memory expansion module power fail interrupt cir-
cuitry should not be relied upon for system shut down notice.
Chapter 4 - Memory Expansion Module Installation
. Board Number Selection
Table 4-4
Board Number
Board number 0
Board number 1*
Board number 2
Board number 3
*Default
Note
Short
1/2, 3/4
1/2
3/4
none
4-5