Chapter 4: Boot Rom Functions; Introduction; Power-Up/Self-Test Sequence - HP 340 Series Service Manual

Boot ROM Functions
4
Introduction
A Revision C1 Series 300 Boot ROM is used in the Model 340 Workstation SPUs. When the
SPU is turned
1
two Boot ROM instruction sets are executed by the CPU:
• Power-Up/Self-Test Sequence.
• Booting Operating Systems.
Power-Up/Self-Test Sequence
VVhen the SPU is turned on the CPU executes the power-up/self-test sequence before an
operating systeln is booted. This is required to initialize and test hardware to make sure
the SPU is ready to boot an operating system. The SPU's power-up sequence is shown below.
1. Test CPU.
2. Determine 24 or 32 bit address range.
3. Turn on self-test LEDs.
4. Test the top 16 Kbytes of RAM.
5. Set up data structures.
6. Search for any boot extension ROMs and call any valid ones.
7. Determine processor type.
8. Initialize and test processor board timer.
9. Reset all I/O.
10. Initialize the video circuits.
11. Checksum the Boot ROM.
12. Display CPU type.
13. Look for floating point co-processor.
14. Initialize keyboard electronics.
15. Drop interrupt level.
16. Preload for main RAM test.
17. Test processor board HP-IB.
18. Test DMA.
19. Test remaining RAM and set up bottom of memory.
Boot ROM Functions
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