HP 330 Service Information Manual page 151

Test and Boot Code Segment
This section explains the sequence the CPU executes Boot ROM test list vectors and loops
through self-test if continuous self-test is enabled.
The Test List (like the Boot List) is a temporary structure used by the Boot ROM to allow
upgrades and extensions. Test and/or initialization code for a given devices does these things:
• Indicate on LEDs the device being tested.
• If the device is present THEN
• If the test initialization fails THEN indicate the failure
• ELSE indicate the presence of the device.
A step-by-step list of what happens in this Boot ROM code segment is explained. As before,
each step is preceded by an indication of that step on the LEDs. The test list for the Boot
ROM is as follows:
1. Which Processor:
The stack is checked to determine the CPU is an MC68020.
2. Initialize Timer:
The Boot ROM initializes and tests the timer on the processor. If a failure occurred, then
the Boot ROM halts with 0516 on the LEDs.
3. Identify Display RAM:
The Boot ROlV1 determines if display RAM is present at 88000016. If there is, then its
presence is noted.
4. Reset I/O:
A RESET instruction is executed to clear all I/O. The Boot ROM sets up the HP-HIL
keyboard electronics to ensure that its timer does not lose time. Keyboard electronics on
an accessory card are not set up.
5. Initialize and Test Video Circuits:
The output hurnan interface soft vectors are set up to to handle the video output circuits
or dumnlY display drivers are set up if no video circuits are present. If alpha video output
circ:uits are present, then a memory test of the alpha, and highlight melllories is executed.
If bit-map video output circuits are present, then its ID /FONT ROM is checksummed
and the circuits are initialized and cleared. If a failure is discovered it is indicated on
the LEDs. The message
SELF-TEST MODE
is shown on the bottom of the display. See the
section on Hurnan Interface for the console selection algorithms.
6. Display Copyright Notice:
The Boot ROlVl displays a 1985 copyright message.
Boot ROM Functions
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