IBM 7013 J Series Operator's Manual page 98

SSBus Maintenance
This option is used to investigate and check devices on the SSBus and is meant only for
trained service personnel.
Use this option to investigate and check devices on the SSBus.
1. Enter 4 in the main menu to select this option. SystemGuard displays the following
menu, which allows you to read the time of day (TOD) registers and to read or write the
non-volatile random access memory (NVRAM) and lines S1 and S2.
2. To read data:
a. Enter a read command number.
b. When requested, enter the start address (hexadecimal) and the length (in bytes).
c. The data at the given start address for the given length is displayed. Then the prompt
for the start address and length is shown again.
d. You can continue the read operation by pressing the Enter key, in which case a new
block of data is displayed.
e. Enter a . (dot) to end the read operation and redisplay the SSBus MAINTENANCE
MENU.
3. To write data:
a. Enter a write command number. The update is performed one byte at a time.
b. When requested, enter the start address.
c. The contents of the specified location are displayed followed by a blank. Enter a new
value followed by the Enter key.
d. The new value is written at the given address and the contents of the next location
are displayed.
e. Press the Enter key (without entering a value) to skip the current location and move to
the next location. In this case, no write is performed and the next location is shown.
f. Enter a . (dot) to end the write operation and redisplay the SSBus MAINTENANCE
MENU.
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Operator Guide
SSBus Maintenance
Command
00 Read
01 Write
02 Read
03 Read
04 Read
05 Read date
06 Read alarm
select(x:exit):
Feature start–end address
NVRAM 0x40000–0x7ffff
NVRAM
Line S1 0x000207f0
Line S2 0x000205f0
TOD 0x38000–0x3803e
TOD
TOD