Expansion board for the CD32

[Stedy]

Hi,

@alexh

Thank you for the source code conversions. You've given me a few ideas to play with and I can see how many resources I need in some candidate CPLDs.

Would you have a testbench for a 68020 processor interface?

@thread

Don't expect a quick design turnaround. All going well, might have something around May, assuming a couple of other projects go Ok.

Can I also ask for some feedback on a few ideas?

I assume you would prefer to use and source your own SIMMs, upto 8Mb rather than have SRAM onboard?
4 MB SRAM costs £10, 8 MB costs £20

For IDE I'm planning to fit a compact flash connector, any objections?

For a floppy interface, a 34 pin header is easier and cheaper than 23 way d-types for external drives.

A CPU/FPGA accelerator would be a later design, depending on how this design progresses and the CPU cores themselves. It would of course cost more.

Ian

[kipper2k]

Originally Posted by Stedy

Hi,

@alexh

Thank you for the source code conversions. You've given me a few ideas to play with and I can see how many resources I need in some candidate CPLDs.

Would you have a testbench for a 68020 processor interface?

@thread

Don't expect a quick design turnaround. All going well, might have something around May, assuming a couple of other projects go Ok.

Can I also ask for some feedback on a few ideas?

I assume you would prefer to use and source your own SIMMs, upto 8Mb rather than have SRAM onboard?
4 MB SRAM costs £10, 8 MB costs £20

For IDE I'm planning to fit a compact flash connector, any objections?

For a floppy interface, a 34 pin header is easier and cheaper than 23 way d-types for external drives.

A CPU/FPGA accelerator would be a later design, depending on how this design progresses and the CPU cores themselves. It would of course cost more.

Ian

Hi Ian,

my prefs would be 8mb SRAM seeing as there is no pcmcia slot to fight with, CF card adapter for IDE and 34 pin header is fine for a floppy. An accelerator would be good as a later on project, i would rather have something sooner than wait for the whole shooting match..

I'll check for the US/Can keyboard map editor. Boards were mailed to you on Friday so hopefully you'll get them soon

[Amiga1992]

I would also prefer an all-in-one already made solution including the RAM than having to go hunt some old SIMMs. WOuldn't onboard SRAM be faster?

CF slot instead of straight up IDE sounds good to me.

I don't care about either a floppy drive connector or CPU/FPU upgrades, so I leave that to your best judgement.

[Lord Aga]

Originally Posted by kipper2k

my prefs would be 8mb SRAM seeing as there is no pcmcia slot to fight with, CF card adapter for IDE and 34 pin header is fine for a floppy. An accelerator would be good as a later on project, i would rather have something sooner than wait for the whole shooting match..

Seconded !
A perfect starter boost

[alexh]

Originally Posted by Stedy

I assume you would prefer to use and source your own SIMMs, upto 8Mb rather than have SRAM onboard?

Take care if you add a SIMM slot. DRAM comes in various configurations. The HDL for the A608 I *believe* relies on having a particular DRAM config (4Mx8 rather than 2Mx16 or something like that).

[TreacleWench]

IDE and 8MB on-board RAM in my opinion. I don't want to hunt for SIMMs and I don't know why anyone would want 4MB. I would say that a CF socket is fine for IDE unless other people want the option of adding more devices through a 4 way buffered interface. Floppy interface would be nice but not essential. An accelerator doesn't interest me, like most others my CD32 is for games only (it actually sits under the living room TV next to my PS3 ) and an accelerator only reduces compatibility.

Really excited to get this and Kipper2k's board

[fitzsteve]

Originally Posted by akira

i would also prefer an all-in-one already made solution including the ram than having to go hunt some old simms. Wouldn't onboard sram be faster?

Cf slot instead of straight up ide sounds good to me.

I don't care about either a floppy drive connector or cpu/fpu upgrades, so i leave that to your best judgement.

+1

[kipper2k]

It will be nice to have a CD32 that has the benefits of A1200 compatibility with the built in CDROM and having the expandibility too. It has been under the TV or in the loft for too long . If you don't have a PS/2 keyboard, go looking for one

[Jope]

Originally Posted by Stedy

For a floppy interface, a 34 pin header is easier and cheaper than 23 way d-types for external drives.

Perhaps have the provision for the user to solder his own PCB mount 23pin D connector? There's plenty of old A500s and such to scavenge these from.

[Amiga1992]

But with a normal 34 pin disk drive header you can use a more widely available internal floppy drive instead of a less available external Amiga floppy drive.

[fitzsteve]

Originally Posted by Akira

But with a normal 34 pin disk drive header you can use a more widely available internal floppy drive instead of a less available external Amiga floppy drive.

And floppy emulators

It would be possible to make a nice internal solution for those hackers out there...

[alexh]

I'm pretty sure it's too late to add an external floppy disk drive interface. It would have to be on the back panel and the PCB design has already been done and prototypes manufactured.

As for an internal floppy disk drive interface, you need to be realistic. On the Amiga there is almost no need for a floppy disk drive connector when you've got a CD-ROM and an IDE hard drive. It just adds cost to PCB & CPLD.

It is NOT just a row of pin headers. The CD32 has no CIA nor Gayle and so portions of these chips which were involved in floppy disk drive control (disk sense, selection, control, stepping ) have to be recreated in the CPLD.

Originally Posted by Stedy

I can see how many resources I need in some candidate CPLDs.

Presumably because A500 & A1200 games work when launched from a CD32 CD-ROM, the emulated CIA's in the Akiko are sufficient for game compatibility and so I believe you won't need to implement any extra CIA functionality if you are not supporting floppy drives?

[Amiga1992]

Yeah I wouldn;'t care AT ALL about a floppy connector.

[sanjyuubi]

Hi Kipper!

Why to use same CD32 connector for expansion and not any other cheaper edge connector? There isn't any reason to have the same connectors for expansions as yo won't connect anything to that slot anyway. So save money, precious CD32 connectors and make it cheaper.

[Lord Aga]

Originally Posted by alexh

As for an internal floppy disk drive interface, you need to be realistic. On the Amiga there is almost no need for a floppy disk drive connector when you've got a CD-ROM and an IDE hard drive. It just adds cost to PCB & CPLD.

Weeeell... Yes if we have CD-ROM and IDE. But this is going to be a CF slot, not IDE, as far as I understood. And CD drives of CD32s are not exactly in their prime. So if they snort out we are left with opening the case whenever we want to add some software. For that reason I would still like to have a floppy connector.

[fitzsteve]

Originally Posted by sanjyuubi

Hi Kipper!

Why to use same CD32 connector for expansion and not any other cheaper edge connector? There isn't any reason to have the same connectors for expansions as yo won't connect anything to that slot anyway. So save money, precious CD32 connectors and make it cheaper.

What about if someone doesn't want the expansion and they just want to use their FMV cart

[alexh]

Originally Posted by Lord Aga

So we are left with opening the case whenever we want to add some software.

Yes.

[Amiga1992]

Originally Posted by Lord Aga

CD drives of CD32s are not exactly in their prime. So if they snort out we are left with opening the case whenever we want to add some software.

You wouldn't need to open the unit, it will be stuck to kipper's connector, so you take the whole thing out and fiddle with the CompactFlash card.

[alexh]

I think that's what he meant by "opening the case", that you have to remove the expansion.

[Amiga1992]

There's no case opening involved in removing the expansion, so I don't understand how he could mean that