Difference between revisions of "VAXstation 100 firmware notes"

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(D0 flags: BBA present.)
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| BBA present.
 
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Revision as of 15:59, 15 February 2023

Random notes from running the firmware in an emulator.

Memory map

Vs100-memory-map.png

Error LEDs

Indicates which test failed. During power-up, green light turned off. During idle loop, green light remains on.

Vs100-diagnostic-led-errors.png

Apparently there's a bug.

VS100-TT-7.png

Interrupts

All VS100 interrupts use the autovector feature.

VS100-interrupts.png

Keyboard test

The firmware transmits code FD (hex) to the LK201 keyboard, which commands it to jump to the power-up sequence and self-test. The keyboard transmits a four-byte message back. The VS100 ignores the keyboard ID, and checks that the third is not 3D.

This information is from the VT220 Technical Manual.
LK201-powerup.png

D0 flags

The firmware maintains a set of flags in register D0.

Bit (decimal) Meaning
16 Manufacturing mode.
17 BBA present.
19 Power-up error.
24 BBA done.
25 Vertical retrace interrupt.