User guide

Failures detected by the SROM-based tests are indicated by the test sequence
halting and the LED display permanently showing the failing test number.
A detailed dump of internal registers, program counter, expected and actual
data is performed either through the serial port of the 21064 or through the
console Universal Asynchronous Receiver/Transmitter (UART). If the Intel SIO is
successfully configured and the console UART test passes, the SROM does all I/O
through the console UART; otherwise, it is through the 21064 serial port/pin.
Failures detected beyond the SROM do not halt the reset sequence, but rather,
the display freezes at the first failing test, and the sequence attempts to continue
to console mode. An attempt is also made to write the diagnostic log to the
console terminal.
You can affect the POST sequence by using certain user-selectable, control
parameters (implemented as environment variables) that allow the initialization
to continue, despite the existence of some errors that you may not wish to treat
as fatal.
4.2.2 Console Prompt Diagnostics
You can invoke some diagnostics directly from the console terminal, and you can
control them by using command options and diagnostic environment variables.
These tests may require operator intervention.
4.3 Diagnostic Test Descriptions
4.3.1 Available Console Diagnostics
Table 4–1 shows the console diagnostic tests and the commands you can use to
invoke them. You can invoke the majority of these tests at the console prompt.
4–2 Diagnostics