What is the maximum size of memory Paula can play under a DMA interrupt?

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What I mean is you point a single DAC to an area of RAM and it will play a certain size of data before needing to be instructed to play again. Is it 64kb or 64bytes? Or is there no limit, you tell it to start playing at address ####### etc and it will move through the memory until you tell it to stop?

I'm sure there was a 64 in it but can't remember and it isn't an obvious answer from google search except that it looks like DMA data exchange max size is 64kb so maybe that's what I am remembering.

[Samurai_Crow]

64 K-words (128 Kbytes)

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Originally Posted by Samurai_Crow

64 K-words (128 Kbytes)

Thank you. Is it correct that one of the instructions to Paula is to keep repeating that 128kb of memory to play a continuous loop?

[Samurai_Crow]

It loops by default.

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Originally Posted by Samurai_Crow

It loops by default.

Magic.

[Photon]

Hey CCCP_Alert! This belongs in the Asm/Hardware forum as this is the perfect forum for a question like this one.

Humm. DMA is instead of interrupts, so there's no such thing as a DMA interrupt. There are audio interrupts, though, which are triggered when a sample window is about to loop. This is not what you asked, but you could set up a chain of such interrupts to play a sample that occupies all 2MB Chip RAM-256 bytes (and then stops, if you wish).

You can also play a 128K sample by starting the first 64K, then when the hardware has read the first sample you can write a sample window 64K higher in memory. But this last window will loop unless you (when THAT has been read) set a silent sample window.

[CCCP alert]

Originally Posted by Photon

Hey CCCP_Alert! This belongs in the Asm/Hardware forum as this is the perfect forum for a question like this one.

Humm. DMA is instead of interrupts, so there's no such thing as a DMA interrupt. There are audio interrupts, though, which are triggered when a sample window is about to loop. This is not what you asked, but you could set up a chain of such interrupts to play a sample that occupies all 2MB Chip RAM-256 bytes (and then stops, if you wish).

You can also play a 128K sample by starting the first 64K, then when the hardware has read the first sample you can write a sample window 64K higher in memory. But this last window will loop unless you (when THAT has been read) set a silent sample window.

Thanks for the info. Sorry it's in the wrong section, I saw the 'how much CPU time does C2P take" thread here so I thought it could go here.

[Photon]

Originally Posted by CCCP alert

Thanks for the info. Sorry it's in the wrong section, I saw the 'how much CPU time does C2P take" thread here so I thought it could go here.

NP. Yeah that could go in the same forum too, for better answers.

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It is an interesting feature though, I need to do some calculations but 64kb for 4 seconds of mono, if not stereo, music sample sections to be looped has some interesting potential for a game with 'unlimited' sound channel music. Good enough for decent TV speaker of 16khz 8bit 4 second loop = 62.4kb and most of the music I make is about 4 second sections you can repeatedly loop and swap out for the 'next bit' this leaves 3 channels for SFX on top.