5 Jun
2010
5 Jun
'10
11:17 a.m.
Brad Parker wrote:
I know it's crazy, but I finally got my FPGA based
PDP-8/I to boot TSS/8.
http://colo3.heeltoe.com/download/pdp8/README.html
It's been sort of working for a while but had some odd bugs. I did a
lot of simulation and comparison
with simh. I think it's pretty close to correct now. There are still a
few bugs to clean up but it seems to run
everything correctly and save files to the disk.
I hope to agument my "disk maker" to extract and rebuild tss/8 file
systems soon. It would be nice
to build up disks from some of the decus programs. Right now it will
extract and replace the
main parts of TSS/8 but not the file system itself.
-brad
Great job Brad. I don't have any interest in pdp8's or the like, but I
do have an interest in verilog, FPGAs, and the general usage of new tech
to reproduce old tech. I want to look at your UART and compare to mine.
Mine is sort of bare bones, but works well. I'm running it at 2mbps
reliably. It's neat to compare how I did things vs other people's
approaches.
I have the sparatan-3e board, but -3 board has some advantages, namely
the SRAM instead of my DDR. Much easier to access from hdl's. For my
project, I've been using FIFO that uses block rams. I have about 45k
block ram space, so it's sufficient for a lot of things.
I've just got my external amiga floppy drive controller rewritten from a
microcontroller application to the -3E FPGA. I was able to make some
huge improvements, not the least of which reading a whole amiga disk
into .ADF format in about 40 seconds. Given standard RPM speeds, 32s is
near the theoretical maximum.
Getting an OS to boot is certainly a huge milestone, and you should be
proud of yourself.
Thanks for posting.
Keith