CD32 eject / disc stop interrupt handling

girv · 17 December 2023, 14:18

I've had a look about and can't find anything on this.

When the CD drive in a CD32 spins down (eg: if you open the lid), a level 2 interrupt is fired, INTF_PORTS is set in INTREQR, and it seems to fire continually after this. I guess Akiko raises this?

Is there any information on how to respond to and clear this interrupt without using cd.device? I'm aware of the devkit note about not messing with INT2 or else this will happen, I just wondered if there was a solution that didn't require cd.device.

I'm porting Rogue Declan to CD32 and reworking it to leave the OS in place enough isn't an option. The game loads fine, it's just that it crashes and/or hangs if the disc spins down.

Toni Wilen · 17 December 2023, 15:50

CD player sends status info when state changes and Akiko sends interrupt when CD has pending data.

If you mean how to disable interrupt in hardware level: Clear $B80008. It is Akiko interrupt enable register (long word register, normal read/write, not like chipset registers)

Save the register contents, clear it, restore value if system needs to be restored. Reading the pending data is much more complex (and isn't necessary)

akiko.cpp in WinUAE sources has Akiko register descriptions.

girv · 17 December 2023, 16:27

Thanks. I'd found those sources and was trying clearing 0xB80018.b but the interrupts kept coming. Clearing 0xB80008.l seems to have done the trick

jotd · 17 December 2023, 16:36

My technique is to use a whdload slave and CD32load on it. I remember Toni helping me with all this interrupt crap & also audio CD stuff.

The documentation is nonexistent, which doesn't help a lot. Sometimes you create something that runs with WinUAE but not on the real hardware, which is super frustrating, specially because you have to burn a CD each time to test it... Fortunately I used a TF328 to store my test code and CD data doesn't need burning over and over. It's also faster.

girv · 17 December 2023, 17:44

Is there a similar interrupt when an IDE CD (on an A1200) is ejected?

EDIT: seems so, in FS-UAE at least. I'm not going to handle this one as the CD controller could be many things.

girv · 17 December 2023, 22:28

I'm also confused with the keyboard handshake. The same code I use on the ADF version, which AFAIK works everywhere, ends up with the first key-up interrupt endlessly repeating (with the correct keycode).

Fixed: my keyboard handshake in the cd32 one had a typo

17 December 2023, 14:18	#1
girv Mostly Harmless Join Date: Aug 2004 Location: Northern Ireland Posts: 1,109	CD32 eject / disc stop interrupt handling I've had a look about and can't find anything on this. When the CD drive in a CD32 spins down (eg: if you open the lid), a level 2 interrupt is fired, INTF_PORTS is set in INTREQR, and it seems to fire continually after this. I guess Akiko raises this? Is there any information on how to respond to and clear this interrupt without using cd.device? I'm aware of the devkit note about not messing with INT2 or else this will happen, I just wondered if there was a solution that didn't require cd.device. I'm porting Rogue Declan to CD32 and reworking it to leave the OS in place enough isn't an option. The game loads fine, it's just that it crashes and/or hangs if the disc spins down.

17 December 2023, 17:44	#5
girv Mostly Harmless Join Date: Aug 2004 Location: Northern Ireland Posts: 1,109	Is there a similar interrupt when an IDE CD (on an A1200) is ejected? EDIT: seems so, in FS-UAE at least. I'm not going to handle this one as the CD controller could be many things. Last edited by girv; 17 December 2023 at 22:18.

17 December 2023, 22:28	#6
girv Mostly Harmless Join Date: Aug 2004 Location: Northern Ireland Posts: 1,109	I'm also confused with the keyboard handshake. The same code I use on the ADF version, which AFAIK works everywhere, ends up with the first key-up interrupt endlessly repeating (with the correct keycode). Fixed: my keyboard handshake in the cd32 one had a typo Last edited by girv; 17 December 2023 at 22:57.

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17 December 2023, 15:50	#2
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,506	CD player sends status info when state changes and Akiko sends interrupt when CD has pending data. If you mean how to disable interrupt in hardware level: Clear $B80008. It is Akiko interrupt enable register (long word register, normal read/write, not like chipset registers) Save the register contents, clear it, restore value if system needs to be restored. Reading the pending data is much more complex (and isn't necessary) akiko.cpp in WinUAE sources has Akiko register descriptions.

17 December 2023, 16:27	#3
girv Mostly Harmless Join Date: Aug 2004 Location: Northern Ireland Posts: 1,109	Thanks. I'd found those sources and was trying clearing 0xB80018.b but the interrupts kept coming. Clearing 0xB80008.l seems to have done the trick

17 December 2023, 16:36	#4
jotd This cat is no more Join Date: Dec 2004 Location: FRANCE Age: 52 Posts: 8,164	My technique is to use a whdload slave and CD32load on it. I remember Toni helping me with all this interrupt crap & also audio CD stuff. The documentation is nonexistent, which doesn't help a lot. Sometimes you create something that runs with WinUAE but not on the real hardware, which is super frustrating, specially because you have to burn a CD each time to test it... Fortunately I used a TF328 to store my test code and CD data doesn't need burning over and over. It's also faster.

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