IBM System/32 Introduction And Maintenance Manual page 279

Mode Selector Switch (Continued)
INSN STEP/DPLY CHKS
With the MODE SELECTOR switch in this posi-
tion, pressing CE START executes the next
sequential micro instruction or a branch. At the
end of each step, the processing unit error byte
and the port error byte are displayed in the
display lights.
The following charts, one for the processing
unit errors and one for PO(t errors, list the
error and cause for each bit:
Processing Unit Error Byte (High-Order)
Bit Error Cause
o
SDR parity Parity is incorrect in the
check SDR.
SAR parity Parity is incorrect in the
check
SAR.
2 Storage gate Parity is incorrect at the
parity check output of the storage gate
in the data flow.
3 ALU gate Parity predicted does not
parity check agree with the parity
generated at the ALU gate.
4
Invalid con-
I ndicates that control stor-
trol storage age was addressed outside
address/ its boundaries.
SARI
5 Invalid main
Indicates that the main
storage ad-
storage address exceeds
dress/SARI the system main storage
size.
6 Not used
7 Microcode Indicates that the micro-
check
program was lost in a loop
for 6 seconds.
I
Bits 4 and 5 both on indicates parity is incorrect in
the SAR.
Port Error Byte (Low-Order Byte)
Bit Error Cause Bit Error Cause
0 DBO parity Incorrect parity was de- 6 Burst mode Any processing unit or
check tected by an attachment
operation port parity check was de-
on the data bus out. check tected during a burst mode
operation.
Invalid Indicates that the port put
device
an address on the DBO but
7
Invalid port
Bits 4-7 of work register
assignment no response was received
o
(high byte) were not
from an attachment within
0000.
the required time. (Port
raised the control out line
to address an attachment
INSN STEP/DPL Y PCR
and the attachment did not
respond by activating the
With the MODE SELECTOR switch in this posi-
service in line within
tion, pressing CE START executes the next
5.4
J1s.) This check can also
sequential micro instruction or a branch instruc-
occur if the DBO has
tion. At the end of each step, the eight bits of
incorrect parity during the
the PCR are displayed in the high-order byte of
transmission of an address.
the display lights.
2 OBI parity Incorrect parity was de-
check tected by the port during
SYS I NSN STEP
the transfer of data from
an attachment.
When the MODE SELECTOR switch is turned
to this position, the STOP light comes on. Each
3 Timeout The channel detected an
time the CE START key is pressed and released,
check error in the normal channel
one system instruction is executed. One excep-
sequence. This check occurs
tion to this is the supervisor call (SVC) instruc-
if an attachment does not
tion; it will not be executed.
deactivate the service in
line within 5.4 J1s after the
If the processing unit is running when the
rise of the service out line.
MODE SE LECTOR switch is moved to the SYS
INSN STEP position, the CE START key must
4 CBI/DBI The I/O lines were not
be pressed and released to complete the system
not zero cleared in time. The check
instruction that was in progress.
is made after the service
out line falls during T6
time after transferring a
byte of data to or from an
attachment.
5 System bus I ncorrect parity was de-
parity check tected on the data sent from
the processing unit to the
port (the check is made
when the service out line is
active), or when data is
being sent to the 62GV
attachment during a burst
mode operation.
Consoles
7-5