Computer Control - HP 11180A Operating And Service Manual

Section IV
everytime an output cycle takes place. Once it is "set'', a
valid reading must be taken before it is reset by the B data
line from the Units Address Counter. Once the flip-flop is
reset , in otherwords when one valid reading has been
counted by the Address Counter, any Home Flag will be
acknowledged.
4-51. COMPUTER CONTROL.
4-52. The main function of Computer Control Enable is to
change the timing sequence on the Storage Flag so that it
acknowledges every trigger signal during the input and
output cycles. Computer Control Enable goes to gate IC45.
This gate allows the Encode signal to recall data from the
MOS Shift Registers during an output cycle only. Computer
Control Enable also goes to IC23, which is the gating
function for both the set and reset of the Storage Flag
4-4
Model l l l 80A
Flip-Flop. This control allows the timing sequence to
properly acknowledge all of the trigger signals.
4-53 . For computer operation, each command of the
computer must be acknowledged by a single flag. This poses
one additional requirement on the Storage, in that when
the 50th reading is taken under a normal sequence, the first
reading is automatically outputted. Normally this takes
only one trigger command; but a computer must give two,
one to take the 50th reading and one to command an
output of the first reading. One false cycle is generated
between the input and the output cycles to alleviate this
problem. This is done by "setting" a flip-flop IC21 pins 1
through 6 at the end of each input cycle through the gate
IC22 pins 11 through 13. This is done only in computer
control. The flip-flop stops one reading from being counted
through IC46 pin 12 and transferring a command to the
normal timing sequence. By skipping one reading, one extra
storage cycle is taken each cycle. But it prevents the
computer from causing a loss of data .
'-1
"
I
tf1 '
I
...
'
'
'.
.j
:J
r
~