Varian Data 620/i System Reference Manual page 98

n
n+l
4.3. 1 Externa I Control
The external control instruction is a single word,
non-addressing instruction. It places a function code,
contained in bits 0-8, on the E bus to initiate a control
operation in an external device.
External Control Timing: cycle
17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
r-T- :
L
_..1.. _ ..... _ _ _ _ _ _
L - -_ _ _ .......... _ _ _ _ _ _ _ _ _ - - '
10
o
Xyy
lIS-bit
I
option
The nine bits represented by XYY are placed on the E bus
for transmission to the peripheral controllers. The device
address is contained in the YY portion of the data, and the
function to be performed by the selected device is contained
in the X portion.
Indexing: No
Indirect Addressing: No
Registers AI tered: None
4.3.2 Program Sense
The sense instruction is a double-word, addressing instruc-
tion that senses the logical state of an external line.
Figure 4-2 shows the execution of this instruction.
SEN Program Sense
Timing: 2.25 cycles
17 16 15 14 13 12 11 10 9 8
7 6
5 4 3 2 1 0
r-T-
I I
I I
10
XVY
1---1- -
I I
I
I
Jump Address
G.L
18-bl.!.
option
I
=
0, word contains an address
I
=
1, word contains an indirect address
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