User`s guide

System Initialization and Acceptance Testing (Normal Operation)
4.3 CPU ROM-Based Diagnostics
The diagnostics run automatically on power-up. While the diagnostics are
running, the LED displays a hexadecimal number; while booting the operating
system, 2 through 0 display.
The ROM-based diagnostics are a collection of individual tests with parameters
that you can specify. A data structure called a script points to the tests (see
Section 4.3.2). There are several field and manufacturing scripts.
A program called the diagnostic executive determines which of the available
scripts to invoke. The script sequence varies if the system is in the
manufacturing environment. The diagnostic executive interprets the script to
determine what tests to run, the correct order to run the tests, and the correct
parameters to use for each test.
The diagnostic executive also controls tests so that errors can be detected
and reported. It ensures that when the tests are run, the machine is left in a
consistent and well-defined state.
4.3.1 Diagnostic Tests
Example 4–4 shows a list of the ROM-based tests and utilities. To get this
listing, enter T 9E at the console prompt (T is the abbreviation of TEST). The
column headings have the following meanings:
Note
Base addresses shown in this document may not be the same as the
addresses you see when you run T 9E. Run T 9E to get a list of actual
addresses. See Example 4–4.
• Test is the test number or utility code.
• Address is the base address of where the test or utility starts in ROM. If a
test fails, entering T FE displays diagnostic state to the console. You can
subtract the base address of the failing test from the last_exception_pc to
find the index into the failing test’s diagnostic listing.
• Name is a brief description of the test or utility.
• Parameters shows the parameters for each diagnostic test or utility.
These parameters are encoded in ROM and are provided by the diagnostic
executive. Tests accept up to 10 parameters. The asterisks (*) represent
parameters that are used by the tests but that you cannot specify
individually. These parameters are displayed in error messages, each
one preceded by identifiers P1 through P10.
4–8 System Initialization and Acceptance Testing (Normal Operation)