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XVME-956 Manual
August 1994
Table 5-4. Board Number Selection (W11)
BOARD NUMBER
SHORT
Board number 0
Board number 1*
Board number 2
Board number 3
1/2, 3/4
1/2
3/4
none
*Default
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. F o r
instance, at power-up time, the ROM-BIOS will scan D0000h for a distinctive bit pattern, (55AAh)
and, i f found, execute the program at that address.
5.3.4 P o w e r Fail Interrupt Jumpers (W10, W5)
When the + 5 V system, (not battery), voltage falls below a trip point (selected 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 5-6 shows which pins to short to select a
particular interrupt. T h e power fail signal remains active until the voltage level returns to a normal
value (above the trip level).
NOTE
Remember that the XVME PC/AT will reset when the VMEbus power
dips to 4.85. However, the memory expansion module power fail
interrupt circuitry should not be relied upon for system shut down notice.
5-5