CD32 Debug Board: a call to arms!

[chiark]

I've just received a CD32 debug board, revision 2.

It's great as it gives me a floppy drive port, monitor out, parallel port, serial port. On it are 2 PLCC CIA chips (391078-01), 5 GALs, a few 74 chips...

(Insanely large version available)


More intriguingly, it appears to have an IDE interface, space for RAM and a mounting point for an 030 processor.

So, I now have three projects:
- Get the IDE interface work
- Get the 030 working
- Get the RAM working

Split up for ease of reading and linking...

 

[Justin]

JAWSOME


QUOTE=chiark;142019]I've just received a CD32 debug board, revision 2.

It's great as it gives me a floppy drive port, monitor out, parallel port, serial port. On it are 2 PLCC CIA chips (391078-01), 5 GALs, a few 74 chips...

More intriguingly, it appears to have an IDE interface, space for RAM and a mounting point for an 030 processor.

So, I now have three projects:
- Get the IDE interface work
- Get the 030 working
- Get the RAM working

Split up for ease of reading and linking...[/QUOTE]

 

[chiark]

IDE interface
The IDE interface needs to have the right code in ROM: from the CATS documentation in the CD32 developer package:

There is also
an IDE port which is functional if you have a special CD32 developer
ROM containing the IDE driver.

The CD32 has 1 ROM chip, which must be a 1MB ROM chip as it fits Kickstart and the CD32 extended bits in there.

I've used Doobrey's splitRom to see what's in there, and the differences between the 1200 and cd32 are in the Bootmenu resource, exec, graphics lib, and SCSI device - 40.4 on CD32, 40.12 in A1200 3.1 ROM... And of course all the stuff in the extended CD32 ROM.

There's a separate SCSI device for the 4000, of course...

So what could the interface be?
- Custom to the CD32. Unlikely
- Use the Gayle chip. Not possible. Gayle not on CD32 motherboard, not on expansion board
- A4000 style interface?

From schematics, the A4000 uses U903 and 904 (74HCT245) for the IDE interface to map onto the data lines, as well as U907 (74HCT174) for address lines.

Whaddayaknow? The CD32 debug board has Motorola "F245" 20 pin SOICs which are Octal bus tranceivers, non-inverting tri state outputs.

And guess what a 74HCT245 is?

The address lines appear to map to one of the PAL devices, which could be doing the duty of the 74HC174...

So is the interface based on the 4000 interface? Interesting

This doesn't help getting the interface working, though... It looks like I'd need a custom ROM but how do I get the existing SCSI.device, which must look after the CD-ROM, and the new SCSI.device to bring the interface up in the same ROM? Or is it intelligent and will it load 2nd.scsi.device?

Any suggestions? Could the necessary code be in the 4000 bonus code module?

Or does anyone have a developer ROM image for the CD32 that they could split with ROMsplit to give some clues?

 

[LTAC]

@Chiark: can u post some pictures please? Thanks.

 

[chiark]

Some notes on connectors:

CN1 - Floppy drive - 23 pin female
CN2 - RGB monitor - 23 pin male
CN3 - Goodness knows! - 4 pin header, 1=KB_CLK 2=/BG on CPU socket(!) 3=Ground 4=CN7 pin 12 (paper out!)
CN4 - Serial - 25 pin male
CN5 - IDE - 40 pin header
CN7 - Parallel - 25 pin female
CN10 - ? - 5 pin header. 1=u9 pin 25, 2=u9 pin 24, 3=u9 pin 23, 4=u9 pin 21, u9 pin 20.
CN11 - ? - 2 pin header 1= /CPU_BR 2=ground

connector Pinout: http://www.hardwarebook.info/CD32_Expansion-port

U1 appears to be an 020 socket, as it is 114 pin, not an 030 socket. Damn!

---------- Post added at 17:49 ---------- Previous post was at 16:52 ----------

J15:
Pin 1-> U1 L12 (from bottom left, letters horizontal, no I)
Pin 2 -> U16B, pin3
Pin 3 -> +5V

J16:
Pin 1->major connector A26 (?)
Pin 2-> U16B pin 2
Pin 3-> +5V

J17:
Pin 1-> U16/17/18/19 Pin 31, U1 M3 (and other connections)
Pin 2-> U16B Pin 30
Pin 3-> +5v

J18:
Pin 1-> U1 M4 (and other connections)
Pin 2-> U16B Pin 31
Pin 3-> +5v

Losing the will to live already. This makes no sense.

 

[jvdbossc]

Nice, hope you can do something with this. A shame that it is an 020 Sure you'll have fun with this one

 

[chiark]

y'know, I'm starting to suspect that the debug board blank bits are there to fill in the blanks of development... The memory sockets (U16-U19) are labelled the same on the CD32 motherboard...

 

[Justin]

y'know, I'm starting to suspect that the debug board blank bits are there to fill in the blanks of development... The memory sockets (U16-U19) are labelled the same on the CD32 motherboard...

not so Jawsome

 

[icbrkr]

I've just received a CD32 debug board, revision 2.

So NOW I know who outbid me on that auction

 

[chiark]

Sorry . You can see I have Plans. Wonder if Dave Haynie might remember anything about it...

 

[Tahoe]

Cool, I got one of those! Exactly the same. Never tried the IDE port though.

It's rumoured the SX1 is actually based on this card...

 

[chiark]

I suspect so. From a brief glance, I guess that it's pretty simple to get the floppy, parallel and serial if you put a pair of CIAs on there, as the other signals needed are on the connector. As are the signals for RGB out.

It's almost more interesting to know what the rest of the PALs are actually there for

 

[rkauer]

BG_ & BR_ are CPU signals:

BR is Bus request, it will freeze the CPU after it gives the BG signal back (BUS GRANTED).

 

[gehtjanx]

interesting to get info on that card, but would be better to preserve it as it was produced and not testing around with it. If you can find out a but and get the pal code, it would be great to make some cd32 expansion. but that also is an dream that never will come true i think

gehtanx

 

[Retroelectronic]

Old old thread, but I was doing a lot of searching before mine arrived, and there was still little information about it.
A couple of lots of these sold on eBay early 2017. A lot of 8, and another lot of 5 were listed at the same time (cheap).
I missed both of those unfortunately, but it seems the same seller dug up another one shortly after that, and I got that one.

Anyway, the mystery of it’s IDE interface solved:
https://www.youtube.com/watch?v=8fQhB4HYwWA