I 2nd this, I built a Zeta V1+PartPortProp combination before jumping into the ECB blackplane+SBC-188+4MEM setup.....and now I am about to start building my backlog of S100 cards. Thankfully I have a running Vector Graphic MZ to test new cards in, so I am going to start with the PROM+RAM board and work on from there.
There are two places outside of the existing S-100 boards (Z80V2, Propeller Console) I would look for "Inspiration" for a new S100 SBC:
-The ZetaV2 + PartPortProp
-The ECB MarkIV SBC + PropIO V2
I believe Wayne W. revised the PropIO to V2 to change how it does wait states to make it more compatible with faster CPUs - there was some discussion about that on the list. Since the Propeller is kind of slow, I think it went to using a flip-flop circuit to automatically asking for wait states with the Propeller un-setting that request, vs the PropIO V1 where the Propeller had to react and ask for wait states (and sometimes it was too slow and problems resulted).
It would be really nice to have:
-A Z80 CPU
-Enough RAM to run RomWBW (512kb + banking circuitry?)
-8-bit ROM
-SD Card Storage (SD cards are much more readily available than CF cards these days, so this would make the board most friendly to new users bringing up a new system)
-Serial UART
-PS/2 keyboard
-Propeller VGA output
-Basic bus diagnostic lights
-Mounting holes for mounting the card on "Feet" without a backplane
-A 5V barrel-plug input for powering the board up without a backplane
All on one board, *and* to make the I/O parts of the board accessible to other potential future CPUs on the S-100 bus as well (similar to the 8080A CPU replacement board which can double as an IO board) so they could be utilized with other S-100 CPU boards later on.
I don't know if floppy or IDE are really a necessity for this board. SD cards are readily available and the ZFDC or Dual IDE boards could be a good first addition to a new user's system. I would argue to keep it simple vs making things more complicated. Using the Z180 chip's built in SPI interface to drive the SD cards like the MarkIV does would be an excellent way to do this - however the Z180's onboard peripherals would not be available to other CPU cards to use, so it might be better to use an SD card implementation that other boards could access later.
Just my two cents.
Andrew B
On Wednesday, September 9, 2015 at 5:30:56 PM UTC-7, Gary Kaufman wrote:
I'd suggest that any single board "piggyback" onto the software
platform that Wayne Warthen and others have done for the N8 / Zeta
systems. His RomWBW is an ideal starter system with CP/M in ROM, and
supporting ram disk, propeller console, serial port, SD memory card
drive and floppy support.
I'd love to see something like the Zeta2/ParPortProp combination on a
S-100 card.
- Gary