CMD QBUS SCSI

Curtis H. Wilbar Jr. rescue at hawkmountain.net
Tue Jan 16 21:54:35 CST 2007


I found the manual for CMD 220 on bitsavers... along with a txt file
for the 220A/TM (which is what I have).

Couple of things:

1. Does anyone have the full manual digitized (or a hard copy you don't want
    anymore) that covers the 220A (to be exact, CQD-BV220A/TM) ?

2. In the txt file, it has (formatting neatend... (for fixed point font 
anyway)):

W1       OUT     Reserved (F)
W2       IN      SCSI terminator power enabled (F)
W3       OUT     Reserved (F)
W4       1-2 IN  Eprom Size 512-Kbit or 1-Mbit (F)
W5       OUT     0 Wait State for Eprom Cycles (F)
W6-1     OUT     Adaptive DMA enabled (F)
W6-2     OUT     Adaptive DMA Dwell Time enabled (F)

W6-4     W6-5
IN       IN      0.8-ms DMA dwell time
OUT      IN      1.6-ms DMA dwell time
IN       OUT     3.2-ms DMA dwell time
OUT      OUT     6.4-ms DMA dwell time

W6-5     OUT     Block mode DMA enabled (F)

W6-6     W6-7    Auto-Boot for LSI-11 systems without Boot Roms
OUT      IN      Auto-Bootstrap address = 773000
IN       IN      Auto-Bootstrap address = 771000
OUT      OUT     Auto-Bootstrap disabled (F)
IN       OUT     Auto-Bootstrap address = 775000

W6-8     IN      Reserved (F)

The W6-4, W6-5 pair I believe should be labelled W6-3, W6-4, as
W6-5 is documented twice ... and W6-3 is not documented.

Anyone know if my belief/assumption is correct ?

Anyone know what DMA dwell time should be used in a PDP11/83 ?

Should this board be closest to the CPU, or furthest in a an 11/83 ?

Thanks in advance,

-- Curt




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