exxos's Atari, Amiga & retro forum

Badwolf wrote: 26 Sep 2025 10:06 Where's the cheaper one?

https://www.ebay.co.uk/itm/306490210835

exxos wrote: 26 Sep 2025 11:51 https://www.ebay.co.uk/itm/306490210835

Ah yeah, cheers. That's the one. I'll get two!

BW

Here's an interesting thread (has a lot of rants, but some good info) on Falcom DMA access and a theory of why Steinberg may wrote specific SCSI/DMA code in Cubase Audio to overcome CPU blocking of DMA access in standard TOS.

https://forums.atariage.com/topic/32321 ... no/page/5/

The Falcon has 3 channels of SDMA, perhaps the 16bit DMA line required specific code to work with SCSI and non blocking CPU to achieve a direct to disk recording and playback system. Also, please note that the DSP is used also for effects, such as Reverb, EQ etc, so that's also why Cubase Audio works with SCSI as it may allow for real time effects for streamed audio files from the DMA line.

I'll take a look thanks. I'm not sure it's a DSP issue yet even.. I mean I can't hardly load cubase a lot of the time before corruption happens. So I assume dsp isn't even used yet...

It seems like ram corruption somehow after loading your music.

Edit:
Another "painful" thread to read it seems.

@exxos have you tried perhaps with a 4 GB Falcon as well? With all the recent sensitivities around 14GB config, those 16 Bit 44.1KHz files are very large. Some are many MBs.
Not sure how does Cubase cache them in memory and where.

whomper wrote: 26 Sep 2025 19:40 @exxos have you tried perhaps with a 4 GB Falcon as well? With all the recent sensitivities around 14GB config, those 16 Bit 44.1KHz files are very large. Some are many MBs.
Not sure how does Cubase cache them in memory and where.

I did some days ago.. I think it only loaded half your song and ran out of ram..

I did wonder if you could do some smaller test song or even just playing some notes or something which would load in a 4MB machine.

whomper wrote: 26 Sep 2025 17:34 Here's an interesting thread (has a lot of rants, but some good info) on Falcom DMA access and a theory of why Steinberg may wrote specific SCSI/DMA code in Cubase Audio to overcome CPU blocking of DMA access in standard TOS.

I think there's a lot of noise and little else on there. PP seems to make the most sense, but his throwaway lines about bus arbitration aren't understood by his interlocutors. Sporniket nails the summary and is ignored.

I don't think it adds to the knowledge base other than mentioning DSP in passing as an optional feature of D2D recordings.

So the question is: does your test case use DSP effects (as this would put the ball back into DSP compatibility camp and reduce the complexity of the issue tremendously)?

BW

Badwolf wrote: 26 Sep 2025 23:30 So the question is: does your test case use DSP effects (as this would put the ball back into DSP compatibility camp and reduce the complexity of the issue tremendously)?

Cubase Audio always uses the DSP for audio processing, even for playback as it has an audio mixer for either 8 or compressed 16 distinct audio tracks. When using 8 tracks, one need to select an audio effect from a drop down list (reverb, eq etc), which probably means it passes through that effect which is uploaded to the DSP. When using 16 tracks audio compression/decompression happens in the DSP.

My test case follows the above.

Could it mean the issue is DSP and clock are getting out of sync?

@whomper I don't think you replied to this post
viewtopic.php?p=134334#p134334

As I don't know if that's how your music is supposed to sound.?

The clicking is the SCSI drive but I suspect the constant ticking noise isn't supposed to be there? If that's the case, then a stock falcon isn't even working...

whomper wrote: 27 Sep 2025 16:21 Could it mean the issue is DSP and clock are getting out of sync?

The DSP is on its own clock, so it's out of sync with the SDMA. BUT the SDMA should take care of that and the SDMA is in sync with the cpu clock. The GAL logic will be driven from CPU timings, that then drives the DSP select lines which are on its own clock.. It does seem a little bit "messy".

My DSP connector is allegedly out for delivery today.. So if it turns up, I'll try and figure out how to wire it up later.