HP 3000 SERIES II System Service Manual page 70

System Service
V BUS
SINGLE CYCLE
TIMERS I ERROR IINTRPT lOP SINGLE STEP
RESET CLOCK
COMPARE
I REGISTER DISPLAY FREEZE
ENABLE HALT REGISTER ALT INHIBIT ENABLE INHIBIT ENABLE
EXT
INHIBIT
Q Q
~ ~ Q Q Q
Q Q Q
~ ~ ~
Q Q
~
INHIBIT JUMP HALT EXECUTE U BUS
NORMAL
ENABLE INHIBIT ENABLE INHIBIT EXECUTE CPU I/O INT
FREE
SINGLE
EXIT JUMP RUN CYCLE
Table 3-1. Maintenance Panel Controls and Indicators (Continued)
PANEL
ROW
11
11
11
11
11
11
11
PANEL MARKING
V BUS COMPARE
ENABLE/INHIBIT
(bistable switch)
V BUS COMPARE
HALT/JUMP (bistable
switch)
V BUS COMPARE HALT
EXIT (spring-return
switch)
V BUS EXECUTE JUMP
(spring-return switch)
SINGLE CYCLE
REGISTER DISPLAY,
REGISTER/U BUS
(bistable switch)
SINGLE CYCLE
REGISTER DISPLAY
ALT/NORMAL (bistable
switch)
TIMERS (bistable
switch)
USE
Enables the V BUS COMPARE HALT/JUMP switch.
When enabled by the switch listed above, selects halt or jump
when the V bus contents are the same as the V BUS COMPARE
REGISTER switches.
When pressed, starts the microprogram after:
•
A halt brought about by the V BUS COMPARE REGISTER
switches.
• A freeze brought about a CCPX-14 special field micro-
instructio n.
When this switch is pressed, the microprogram jumps to the
address in the V BUS JUMP REGISTER switches. This function
should be used only when the computer is halted.
Selects the REGISTER DISPLAY lamp readout as follows:
• With the switch at the REGISTER position, the display is identi-
fied by the lighted REGISTER SELECTION lamp.
• With the switch at the U BUS position, the U bus is displayed.
For this function, the CLOCK INHIBIT/FREE RUN switch
(panel row 11) must be at INHIBIT (single cycle operation).
With this switch at the NORMAL position, RA, RB, RC, and RD
on the S bus
peA
can
be rlispl8yed by the REGISTER DISPLAY
lamps. With the switch at ALT, RA, RB, RC, and RD on theR bus
PCA can be displayed. Also, with the switch at NORMAL, SP1 and
pre-adder are displayed from the S bus; with the switch at ALT,
SP1 and the pre-adder are displayed from the R bus.
This switch must be at NORMAL to store into RA, RB, RC, RD, or
SP1 from the Maintenance Panel.
Enables or disables the CPU, memory, lOP, and selector channel
timers.
3-8