RE: [N8VEM-S100:69] Re: S-100 Motherboard

["Andrew Lynch" <lyn...@yahoo.com>]

Hi Rich!  Thanks!  That's fantastic!  Next up the CPU-Z and booting CP/M!
Please let me know if we need changes to the S-100 backplane and I will
include those in the next revision.

Speaking of interesting homebrew projects, would please tell me more about
your homebrew S-100 6502 CPU board?  That sounds like a great project to add
to the N8VEM and S100computers.com S-100 board collection.  Do you have the
schematics for your board?  Would you be interested in making a version
available for all the builders?  I will gladly write up a KiCAD schematic
and layout a PCB and add it to the collection.

John and I are redesigning the S-100 IDE to be a lot more "builder friendly"
and better support CF adapters.  The prototype board is on its way and
assuming it comes out clean on the build and test the manufactured PCBs will
follow in a few weeks.

Great progress!  This is wonderful!  Thanks and have a nice day!

Andrew Lynch

> -----Original Message-----
> From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On
> Behalf Of Rich Leary
> Sent: Monday, February 21, 2011 2:25 AM
> To: N8VEM-S100
> Subject: [N8VEM-S100:69] Re: S-100 Motherboard
> 
> Today was a mixed day but basically good.
> 
> Before I tried to boot CP/M I tried my 28 (?) year old, wire-wrapped 2
> MHz 6502 CPU board. My S-100 system always had the ability to swap CPU
> boards between Z-80 and 6502. The 6502 board was key to developing my
> OS, DOS/65.
> 
> I pulled the Z-80 board and inserted the 6502 and powered up. It came
> up and since the monitors are basically the same I was able to do the
> same things.
> 
> I powered down and hooked up my 8 inch drives and the hard disk.
> 
> Both CP/M and DOS/65 drives are configured the same:
> 
> A - 8 in SSSD - as configured is always the boot drive
> B - 8 in SSSD
> C - 5.25 in 40 track DSDD (Kaypro IV)
> D - 5.25 in 80 track DSHD (1.2 MB - custom format)
> E - CP/M hard disk partition - 3672 blocks of 2048 bytes per block,
> 256 byte sectors - the first half of the drive
> F - DOS/65 hard disk partition - same size as CP/M partition - the
> second half of the drive
> G - 5.25 in 40 track SSDD (Kaypro II) - same physical drive as C
> 
> I powered the system up with the 6502 CPU, inserted an 8 in DOS/65
> boot disk and wonder of wonders DOS/65 came up and worked perfectly. I
> did not actually hook up the 5.25 in floppy drives so did not test
> them yet.
> 
> The F drive worked perfectly just as it had when I last used the
> system three years ago.
> 
> I also re-confirmed that there is a bad sector on drive E and it is in
> the directory area of that partition. That  is also consistent with
> what I saw last time I brought either CP/M or DOS/65 up. As an aside -
> the system has no provision to remap bad tracks and the Xebec S1410
> controller will only allow entire tracks to be flagged as bad. You can
> not reformat a single sector or flag a single sector as bad - only
> full tracks. That is something I will have to work or I will just wait
> for the new IDE controller board.
> 
> With the success I had it was time to power down and put the CPU-Z in
> the system and try to boot CP/M.
> 
> No joy! I did not get a head load and that should happen as soon as I
> issue the boot command under the monitor.
> 
> I did not get a chance to sort out the problem but I suspect it is
> associated with one of the alternate bus signals that may conflict
> with what I use with the floppy controller. The CPU-Z has provisions
> to use almost every possible signal while the 6502 CPU board has much
> less in the way of alternate signal use. In my old system some lines
> were pulled high or low to maintain everything in a known state. So I
> just need to check those bus signals and check how the CPU-Z uses the
> lines not normally used by the floppy controller. I am sure it will
> prove to be a simple issue and a simple fix.
> 
> Rich