13
DEC 3000 AXP Firmware ROMs
This chapter covers the following topics:
• DEC 3000 AXP firmware ROM format (Section 13.1)
• System and I/O ROM contents (Section 13.2)
• System ROM format (Section 13.3)
13.1 DEC 3000 AXP Firmware ROM Format
The firmware is contained in three ROMs:
• 64 KB Serial ROM
• 256 KB System ROM (part of the SFB logic) in 500/800/900 systems only
• 256 KB I/O Board ROM
The CPU accesses the Serial ROM (SROM) one bit at a time.
• In 300 models, the SROM code consists of only one program in a Xylinx 1765
PLCC SROM.
• In other systems, the SROM is a standard 64 KB ROM (part of the SFB
subsystem), which contains 8 8-KB programs. One is the code that is used in
normal system operation. The others are mainly manufacturing test tools.
The system and I/O ROMs contain header data and code.
• In 300/400/600/700 models, the contents of both ROMS are read 32 bits at a
time.
• In 500/800/900 models, the system ROM is presented one byte at a time to
the CPU, while the I/O ROM is presented 32 bits at a time to the CPU.
13.2 System and I/O ROM Contents
These firmware components reside in the system ROM:
• PALcode (VPP/OSF)
• Console program
• Serial communications controller (SCC) driver
• SCSI Driver
• Graphics port driver
• ASIC Self-test
• NVR Self-test
• Shareable routines (PROM$ routines)
DEC 3000 AXP Firmware ROMs 13–1
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