
Troubleshooting
Boot ROM Selftests
4-4
Boot ROM Selftests
Selftests are called by a bootstrap program resident in the Boot ROM. The Selftests initial-
ize and test the board computer hardware needed to find and boot an operating system. I/O
portions for the console and boot path are tested by the I/O Dependent Code (IODC) for
each I/O function. Selftest runs from PDC I/O address space except for some portions of
the cache test, which downloads itself to memory. Selftest code is not accessible for
change by users.
Users have some control as to what tests are automatically executed at power-on or can
manually gain access by pressing the Rst/Abt switch to the Rst (Reset) position. Users can
also run specific Selftests using the Boot Console User Interface by pressing Esc when
asked for during Normal Mode boot.
Selftests along with console and boot IODC verify that ISL/SYSBOOT can be loaded and
run. In Normal Mode, all operations will stop if a test fails.
Boot ROM Selftests are run on the following circuits:
CPU, floating-point and TLB
I/O and memory controller
VME I/O conversion
If the board computer is installed in a Model 748 VMEbus System, that system’s
EISA module will also be tested.
Since Selftests exercise key hardware parts, an error normally means the boot process
stops. LED’s indicate progress, status and errors. Selftest sequence, status and LED error
codes are listed later in this section. A circuit is usually identified by the error and the
field-replaceable unit having that circuit should be replaced.
The only performance limit is a reasonable amount of time is needed. From power-on to
displaying the first console message for a 16-Mbyte installation is about 15 seconds. More
memory requires a longer time.
Typical Selftest time without failures in Normal Mode with FASTBOOT, 32 Mbytes, is
less than 8 seconds.
When the board computer first powers up, the CPU starts executing Boot ROM code.
Before code is executed to boot an operating system, several things need to be set up and
tested. The Boot ROM has several code segments to manage these responsibilities.
Summary of Contents for 9000 Series 743
Page 6: ...Electrostatic Discharge ESD Precautions vi ...
Page 17: ...1 1 1 Product Information ...
Page 31: ...2 1 2 Functional Description ...
Page 58: ...Functional Description Power Distribution 2 28 Figure 2 9 Power Distribution Diagram ...
Page 59: ...3 1 3 Configuration ...
Page 91: ...4 1 4 Troubleshooting ...
Page 125: ...5 1 5 Field Replaceable Units ...
Page 159: ...6 1 6 Reference Documentation ...