Modifying microcode

[Noel Chiappa]

    > From: Henk Gooijen

    > My findings so far :
    >   www.pdp-11.nl/pdp11-35/repair/repair35page.html
    > Comments are very welcome!

I got a:

  You don't have permission to access to this document on this server. 
  Apache Server at pdp-11.nl

error message?

    > I vaguely remember that there was a difference in the front console For
    > the BA11-K and the BA11-F configuration. ... the two ribbon cables from
    > the front panel are at the right side for a BA11-K box, and on the left
    > side for the BA11-F box. Given the location of the CPU boards in both
    > boxes, that makes sense.

They didn't do two different console PCBs, did they? It must be just cabling
routing? I couldn't find any manual/drawings for the BA11-K version, so I
can't tell for sure..


    > From: Jon Elson

    > I'd get an FPGA development board and download Xilinx's webpack
    > software. It would not take real long to design the basic microcode
    > engine, and then you could develop some application microcode in
    > parallel with the hardware

That approach worked really well for Dave B and I on the QSIC. IIRC, we
bounced around the uengine design concepts for a couple of days, and then
once we decided to go, he had the hardware working in a day or so. It's in
Verilog, so perfect for an FPGA devel board; I think it's in his Github
repository:

  https://github.com/dabridgham/QSIC

If you go this route, I have that config-file driven uassembler written in
portable C (compiles on 3 different systems that I know of) which uses only
standard I/O library which you can use for the ucode; it should handle most
any uengine design, unless it has something really wierd.

	Noel