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HP 9895A Disc Memory Command Set A-9
Commands
The details of the 9895A HP-IB command set are given in this section. The following
conventions are used:
P
P
D
P
P
E
ADDR
P
ATN
Eor
UUUU
or
UNIT
Stat 1
Stat 2
Byte sent between the bus controller and the 9895A.
Parallel poll disabled.
Parallel poll enabled.
The 9895A's current HP-IB device address.
HP -IB parity bit.
HP-IB bus control signal; this signal indicates that a com-
mand is present on the bus.
End or identify; this signal specifies that the present data
byte is the last of the sequence or, if ATN is concurrently
asserted, then a parallel poll is being conducted by the bus
controller.
Unit number (0
<=
UUUU
<=
3).
Status one word:
Most significant byte is S1;
Least significant byte is unit number.
Status two word.
The bit numbering notation for words is as follows:
15 14 13 12
11 10 9 8
7 6 5 4
3 2 1 0
x
X X X
XXXX
XXXX
XXXX
All command sequences are verified for validity when received. This involves testing the
secondary command, the command number and the number of data bytes in the command
sequence for correctness. An I/O program error is defined whenever there is a problem
with a command sequence.
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