have an extra M105 + M7821 unibus card?
ard at p850ug1.demon.co.uk
Tue Jan 31 16:06:21 CST 2006
> Turns out the RX02 emulator needs an M105 and M7821 single height UNIBUS
> card to work.
> Anyone have an extra M105 and M7821?
> I've never seen one of these, but that doesn't mean much. Are they common?
They used to be very common. Original Unibus SPC cards were dual height
and fitted into connectors C and D of the slot. You put an M105 address
selector in connector E and an M782 (or M7820, M7821) interrupt logic
board in connector F
The M105 is the address selctor. It decodes the address from the Unibus,
generates SSYN as appropriate and supplies 4 decoded regsiter select
lines and read/write lines to the peripjheral controller. The M7821 is
the interrupt logic, it handles the bua master part of the interrupt
sequence, supplies the vector, etc.
I haev no idea where you'd find one now. 'In DrARD's junk box' is not a
useful answer, although true. I also have (I think) some 3rd party dual
height boards that fit into connectors E and F and perform both
> Also, does any one have Schematics for the M105 and M7821? I looked on
> bitsavers and did not find anything.
Try looking in the printsets for early SPC devices (KL11, PC11, DR11-A,
etc). Some of those should include the M105 and M7821 schematics.
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