exxos's Atari, Amiga & retro forum

Posted: **Sun Jun 16, 2019 6:43 pm**

Nope...TF534 & TF520 producing green screen on my cdtv...

Posted: **Sun Jun 16, 2019 7:27 pm**

534 Works here with the latest firmware

Posted: **Sun Jun 16, 2019 10:04 pm**

Found this in cdtv.device

ROM:000003E0 ; =============== S U B R O U T I N E =======================================
ROM:000003E0
ROM:000003E0
ROM:000003E0 sub_3E0:                                ; CODE XREF: ROM:00000146↑p
ROM:000003E0                                         ; ROM:000001A0↑p ...
ROM:000003E0                 moveq   #0,d1
ROM:000003E2                 move.l  a6,-(sp)
ROM:000003E4                 movea.l (unk_4).w,a6
ROM:000003E8                 jsr     -$C6(a6)
ROM:000003EC                 movea.l (sp)+,a6
ROM:000003EE                 tst.l   d0
ROM:000003F0                 rts
ROM:000003F0 ; End of function sub_3E0
ROM:000003F0

EDIT: its the only call to allocmem in cdtv.device

Posted: **Sun Jun 16, 2019 10:12 pm**

Ok found the rom location of that code...

Code: Select all

ROM:00F0407C word_F0407C:    dc.w $7200

So i guess i need to patch this location with $7201

Posted: **Sun Jun 16, 2019 10:36 pm**

Will this subroutine be called each time CD is thrown in? Can You redirect it on the fly? We can also patch cdtv.device in extended rom in worst case...

Posted: **Sun Jun 16, 2019 10:39 pm**

8 Bit Dreams wrote: ↑Sun Jun 16, 2019 10:36 pm Will this subroutine be called each time CD is thrown in?

I guess we can find out by testing a CDTV in WinUAE with that as a breakpoint.

Can You redirect it on the fly? We can also patch cdtv.device in extended rom in worst case...

Patching a single ROM location is easy but i have a suspicion that this rom is mirrored in a few places. we'll need to check its not executed at 0xE0xxxx or $A8xxxx

EDIT: Tested in winuae. definitely does get called multiple times during boot.

Posted: **Sun Jun 16, 2019 10:51 pm**

Fair enough, that's why im thinking about patching cdtv.device, so we don't get bugs under different circumstances..

Posted: **Sun Jun 16, 2019 10:58 pm**

Generally would prefer no patching in firmware. But if it’s a single byte then I could do a man in the middle stunt and only patch if the rom read as $2700. That would be safe on all machines and you could decode all the mirrors.

Posted: **Mon Jun 17, 2019 2:11 pm**

I have made a lots of testing with burned CDs with CDTV. I have tested at least 4 different CD burners and burned CDs only works IF you burn them max 5x speed. Burning CDs with 32x wount work. There is no sensible explanation for this, I know.

Posted: **Mon Jun 17, 2019 2:17 pm**

This is what Toni Wilen (winUAE dev) said about a CDTV

CDTV + accelerator can have multiple problems:

- CDTV CD drive is DMA capable and can't access any RAM outside of first 16M address space (24-bit Z2 limit)
- CDTV CD autoconfig board must be located at $e90000 (=must be first 64k Z2 IO device in autoconfig chain. It is autoconfig but ROM driver uses hardcoded addresses..). Accelerator may have its own 64k IO board which will conflict with CD device. Simple workaround is to make sure accelerator Z2 IO (If it even has one) is at least 128k in size.
- Even if accelerator has only "24-bit" RAM (max 8M), it most likely don't have any external DMA support.

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