MiSTer FPGA Forum

akeley wrote: ↑Mon May 23, 2022 10:18 am Well, if it could be made to work in some non complicated manner (like a custom ROM) it'd be interesting option, even without CD Audio.

There are about 130 CD32 + 24 CDTV games available as WHDLoad or hdfs, guess that covers the most important/popular ones. I think most lack the CD32-specific music and voice as well though.

Caldor wrote: ↑Mon May 23, 2022 12:11 pm Defender of the Crown 2 does seem to have a WHDLoad version, but I wonder how that works, given it has voices for the game. It also has CD audio and reading up on the WHDLoad version it seems some scenes rely on waiting for CD audio to finish playing for a scene to end... so I guess the WHDLoad version might not fully work? This would have that same problem with this method of playing it though since we would still lack the CD audio.

akeley wrote: ↑Mon May 23, 2022 2:22 pm

Caldor wrote: ↑Mon May 23, 2022 12:11 pm Defender of the Crown 2 does seem to have a WHDLoad version, but I wonder how that works, given it has voices for the game. It also has CD audio and reading up on the WHDLoad version it seems some scenes rely on waiting for CD audio to finish playing for a scene to end... so I guess the WHDLoad version might not fully work? This would have that same problem with this method of playing it though since we would still lack the CD audio.

DotC is one of my favourite games and so I've tried this version some time ago. Yes, it's quite mute, I guess all these WHDL versions of CD32 games which had actual CD content are kinda "rips" (some actually say "no voice" or "no music" in the name). Maybe the other WHDL versions are "complete" because I don't think all CD32 games had extra CD features, they were just A500/1200 games on a CD (but I might have that wrong, not a big expert on these CD based Amigas).


@Moondandy: I found a CDTV service manual in my docs, attached here, there are some schematics inside but not sure if this is what you're looking for.

KremlingKuthroat19 wrote: ↑Mon May 30, 2022 1:32 pm Thanks for your extensive work on CD32 Caldor! It's great that an FPGA developer is interested in adding CD32 support to the existing core.

Caldor wrote: ↑Wed May 25, 2022 7:04 am There is also an FPGA developer that contacted me, interested in trying to get CD32 support for the MiSTer. He is working on other cores as well though.

lomdar67 wrote: ↑Wed Oct 05, 2022 2:02 pm

Caldor wrote: ↑Wed May 25, 2022 7:04 am There is also an FPGA developer that contacted me, interested in trying to get CD32 support for the MiSTer. He is working on other cores as well though.

Any update on this?

First of all, big thanks to Caldor for your very useful tutorial. Everything works perfectly. I have a CDTV and an Amiga 2000 and I would like to recreate the same system on my Mister withe ISOs support. I would like the kickstar to start with animation and, if the cd was inserted in the primary slave, it would boot the startup sequence of the cd, or exit the cdtv menu and load the hdf workbench. I made a custom rom kickstart 1.3 with scsi support for the hard disk, file system for mister, loaded the share folder, and also mounted two virtual floppy drives with the Mimic application. Everything OK. The problem is that i can't load the CD0. (The hard disk has two partitions of 1Gb each, formatted PSF3. Workbench is 1.3.3 rev. 34.34; SCSI.device Is version 40.12). I also made a second custom rom with CDTV extende 2.35. I noticed that on WinUAE it works perfectly. CDTV animation, read the cd, boot the CDTV logo and then load the game. But not on the Mister.( I just got boot screen 1.3 with floppy request or boot to hdf and workbech if inserted). Assuming that the custom rom works, how do I mount the CD0? What driver and filesystem should I use? Any suggestions. I probably made a big mess and I don't know how to fix It... I'm becoming crazy

I have made that CDTV 2.35 as well. I think the problem is the CDTV is based on SCSI, and the MiSTer Minimig core only has IDE.

With emulation similar to the Amiga CD32 emulation it should be possible to boot at least from ISO images in some CDTV games. Some of the boot floppies for CDTV does work, but you will have to set the core to run with the 68000 CPU and not the 68020, because that seems to be one of the things CDTV games are looking for.

I suspect its the copy protection in the CDTV maybe that checks for the CPU type, but might also just be the emulator thing running CDTV that checks for it, because at least the 2.35 ROM should allow for 68030... which I guess might not be enough for it to also accept 68020.

Would be very nice to be able to use the 2.35 ROM on the Amiga core, but I think it would require so many changes to it that it would become its own branch of the core, to be able to support all the CDTV specific features and hardware. SCSI, CD drive and... I think there are some other things as well.

I am pretty sure it should be possible to make a custom ROM that could support all of this, but my attempts at making a custom ROM that would accept CD images in the shared folder so far failed and I have been hoping to first see some changes made to the core that would help add more CD32 support and CDTV.

I'm not aware of any copy protection whatsoever in CDTV.

The Wikipedia article on the CDTV leads to the article on the A570, which was an external drive unit for the A500. That unit apparently allowed for CDTV compatibility, where third-party CD drives, IDE or SCSI, did not, so Commodore was definitely doing something weird with the interface.

The article says this:

The A570 had no need for drivers. It was automatically recognized as a standard Amiga expansion card by the Amiga Zorro bus Autoconfig feature. Programs for playing Audio CDs were available on a bundled 'A570 Tools' floppy disk, public domain software disk collections, and then on Aminet.

So apparently CDTV games and programs were poking hardware directly in some fashion. It sounds like a real mess.

rhester72 wrote: ↑Fri Dec 09, 2022 12:04 pm

I'm not aware of any copy protection whatsoever in CDTV.

Its described here:
https://cdtvland.com/os235/

"Waaay back in the early 1990s, when CDTV launched, Commodore decided that only registered CDTV developers who paid a licensing fee and royalties were allowed to create bootable CD-ROMs. This was “enforced” by requiring the presence of a special file (named CDTV.tm) on the CD-ROM for it to be bootable. This file contains copyrighted code and the trademarked CDTV logo. Including this file on a CD-ROM without owning a license would technically be breach of copyright. While necessary back in the early 1990s when CDTV was an economically viable platform, today it is nothing more than an unnecessary technical hurdle for CDTV users who just want to author bootable CD-Rs for personal use on their CDTV player."

I am not sure its that much of a copy protection thing, but for no good reason the CDTV looks for the CDTV.tm file or it wont boot. Part of what the 2.35 ROM update, a custom ROM made by the community, does is removing that silly check which was part of why it was so tedious to try to create custom CDTV CDs. Many have still done it though, with the CDTV.tm file and everything. I guess its not so much for preventing the CD being copied as it is to ensure that the ones making the CD has the official tools for making CDTV CDs.

But yeah, there are also some hardware checks I think. Which is also not really copy protection I guess, but more that the hardware is expected to be there.

I read the article you referenced, but the problem is the A570 (and many software solutions that came later) which don't seem to require the license to be present at all. I suppose it's possible it was only on true CDTV hardware, but it would seem more than pointless given the A570 was quite literally intended to turn an Amiga 500 into a CDTV.

rhester72 wrote: ↑Sun Dec 11, 2022 9:42 pm

I read the article you referenced, but the problem is the A570 (and many software solutions that came later) which don't seem to require the license to be present at all. I suppose it's possible it was only on true CDTV hardware, but it would seem more than pointless given the A570 was quite literally intended to turn an Amiga 500 into a CDTV.

Should be the same with the A570:
http://eab.abime.net/showthread.php?t=53936&styleid=4

Not sure if there might be other kickroms that might bypass the CDTV.tm requirements that works with A570, but it should require it.

Sorry, I wasn't referring to autoboot - obviously the A500 won't, given it predates CD-ROM technology, without some serious help. LOL

A500s supported autoboot from Kickstart 1.3 forward. Before that, booting from floppy was the only option, but 1.3 allowed you to boot from pretty much any arbitrary device that supported the concept, including the recoverable RAM disks that started to appear around then. So it should support autoboot from the CDTV. The fundamental capability is definitely there; booting from a hard drive on an A500 or A2000 was dead simple.

How it actually works, however, is something I've never learned. I don't know if the CDTV requires a certain ROM revision, or if it provides its own ROM. Devices could do this, so an onboard CDTV ROM that loaded into RAM and then demanded the CDTV.tm file is one possibility.

Since the A570 was intended to retrofit CDTV capabilities to a regular A500, I assume that's probably how it worked. Actual CDTVs could well have had the requirement in the console ROM, but A570s probably had to autoload a custom driver, so that's probably the ROM that would need patching.

Much of this post is speculation, treat it accordingly. Commodore could have done all kinds of crazy stuff; AmigaOS was super flexible.

edit with one example: they could have required Kickstart 2.0 or later, which could easily have the CDTV.tm requirement embedded.

1.2 actually supported autoboot but it didn't work due to a very subtle bug that was fixed in 1.3. As the VAST majority of A500s shipped with 1.2, there was no assumption on the part of the makers of the A570 that it would work in that fashion.

It's not magic, all it requires is simple of the analysis of the CDTV ROMs. I've added it to my to-do list of projects...but it's very long, so take that for what it is. =) I'm quite intellectually interested now, as this is certainly the first I've ever heard of CDTV licensing (and I'm quite certain Walnut Creek didn't know!).

For the record, CDTV-CR actually did intend to use 2.04.

rhester72 wrote: ↑Wed Dec 14, 2022 3:49 am

1.2 actually supported autoboot but it didn't work due to a very subtle bug that was fixed in 1.3. As the VAST majority of A500s shipped with 1.2, there was no assumption on the part of the makers of the A570 that it would work in that fashion.

I don't have the knowledge to directly comment about that, but autoboot didn't work in 1.2, whether it was intended to or not, so if the CDTV was intended to work with 1.2, they would have needed to do something tricky with its ROMs.

It's not magic, all it requires is simple of the analysis of the CDTV ROMs. I've added it to my to-do list of projects...but it's very long, so take that for what it is. =) I'm quite intellectually interested now, as this is certainly the first I've ever heard of CDTV licensing (and I'm quite certain Walnut Creek didn't know!).

I'm unclear on who Walnut Creek refers to?

I could probably learn how to read the ROMs, since I've worked a little bit with 68000 assembly, but wouldn't bother unless it somehow helped with the CD32 port. I believe that's blocked on completing the Akiko chip, which I can't help with at all. Understanding the CDTV ROMs looks like a moderately fun but irrelevant tangent.

Most A500 were Kickstart 1.3. 1.2 was around for just a year of the A500 and was rapidly displaced by the 1.3 500's

FPGA64 wrote: ↑Wed Dec 14, 2022 6:43 pm

Most A500 were Kickstart 1.3. 1.2 was around for just a year of the A500 and was rapidly displaced by the 1.3 500's

In Europe, perhaps, but definitely not in the US. The VAST majority of US-sold models were 1.2 (but obviously upgradable).

Malor wrote: ↑Wed Dec 14, 2022 6:20 pm

I'm unclear on who Walnut Creek refers to?

They created a good bit of "unlicensed" CDTV content sold in the US.

Malor wrote: ↑Wed Dec 14, 2022 6:20 pm

I could probably learn how to read the ROMs, since I've worked a little bit with 68000 assembly, but wouldn't bother unless it somehow helped with the CD32 port. I believe that's blocked on completing the Akiko chip, which I can't help with at all. Understanding the CDTV ROMs looks like a moderately fun but irrelevant tangent.

Oh, that's the only purpose of it for me - as an interesting intellectual tangent. Never heard of CDTV 'copy protection' before and keen on seeing how it's used (and why).

rhester72 wrote: ↑Wed Dec 14, 2022 7:08 pm

Malor wrote: ↑Wed Dec 14, 2022 6:20 pm

I'm unclear on who Walnut Creek refers to?

They created a good bit of "unlicensed" CDTV content sold in the US.

Malor wrote: ↑Wed Dec 14, 2022 6:20 pm

I could probably learn how to read the ROMs, since I've worked a little bit with 68000 assembly, but wouldn't bother unless it somehow helped with the CD32 port. I believe that's blocked on completing the Akiko chip, which I can't help with at all. Understanding the CDTV ROMs looks like a moderately fun but irrelevant tangent.

Oh, that's the only purpose of it for me - as an interesting intellectual tangent. Never heard of CDTV 'copy protection' before and keen on seeing how it's used (and why).

The Akiko chip in the CD32 is rarely used by anything. Except make the Akiko do chunky2planar... often used in 2.5D games, but the MiSTer already supports that part of Akiko.

This is why CD32 games can be emulated on the Amiga 1200. Some claim that Microcosm uses Akiko, but it does not seem it does. But, I guess Akiko might be used for the CD part, which I guess a CD32 emulator on the A1200 wont need. So a CD32 core might need Akiko for more games than the Amiga 1200 would using emulation.

Akiko was responsible for controlling the CD drive in the CD32 as well as being the controller for the Keyboard and serial. The Chunky 2 planar part wasnt used much if at all. The CD32 was a commercial flop and so no one would spend the time to develop for a niche machine when you could just crank out a A1200 game