5 Mar
2016
5 Mar
'16
5:01 a.m.
So here's a quick update on where Dave Bridgham
and I are with the
QSIC ... We have the first of two wire-wrap prototype QBUS motherboards
more or less (see below) done .. the hardware is 'mostly' working; most
of the work from here on out will be FPGA, etc, programming. There
_are_ a few additional QBUS lines used for bus master (DMA) and
interrupts which we haven't used yet, and one of the first things done
now is to get those two kind of bus cycles working
...
With that in hand, we can do the first controller (RK11), using memory
in the FPGA to simulate a small disk.
Well, Dave has made a big step down that road; he has DMA working (both the
bus arbitration cycle for DMA, as well as master-mode transfers to and from
QBUS slave memory).
He's now starting in on interrupt cycles; once those work, he effectively has
emulation of a minimal small RK (he already has all the registers, since he
needs them to control the DMA to and from the RAM disk). At that point I
should be able to test it by making it the swap drive on a Unix V6 load.
Noel