Xycom XVME 200, Manual

Page: 45 / 57

XVME-200/290 Manual
December, 1987
Signal
Mnemonic
IACK*
IRQl*-
IRQ7*
LWORD*
(RESERV-
ED)
SERCLK
SERDAT
SYSCLK
Table A-l. VMEbus Signal Identification (cont’d)
Connector
and
Pin Number
1A:20
1B:24-30
lC:13
2B:3
lB:21
1B:22
1A:l0
Signal Name and Description
INTERRUPT ACKNOWLEDGE: Open-collector or three-
state driven signal from any master processing an
interrupt request.
It is routed via the backplane to
slot 1, where it is looped-back to become slot 1
IACKIN* in order to start the interrupt acknowledge
daisy-chain.
INTERRUPT REQUEST (l-7): Open-collector driven
signals,
g e n e r a t e d b y a n i n t e r r u p t e r , w h i c h c a r r y
prioritized interrupt requests.
Level seven is the
highest priority.
LONGWORD: Three-state driven signal indicates that
the current transfer is a 32-bit transfer.
RESERVED: Signal line reserved for future VMEbus
enhancements. This line must not be used.
A reserved signal which will be used as the clock for a
serial communication bus protocol which is still being
finalized.
A reserved signal which will be used as the
transmission
line for serial communication bus
messages.
SYSTEM CLOCK: A constant 16-MHz clock signal that
is independent of processor speed or timing. It is used
for general system timing use.
A-4