New Universal Agnus 8372, 75 etc

[braunaudio]

I know it's been said that all the custom chips will be reproduced (at some point), but am hoping that this will include the Super DMAC for the A3k due to it's current unobtanium status.

[pandy71]

Originally Posted by Bruce Abbott

I'm against adding 'improvements' where they aren't really needed.

Paula wasn't intended to be a studio quality audio device, so slight variations in playback frequency aren't important.

-->short
This is a bit contradictory but "not my circus and not my monkeys" so from my perspective EOT.

-->long
Paula is very similar in terms of capabilities to the first Fairlight CMI, beside to this Amiga was used also as serious music machine/audio source... Studio quality definition then is quite vague...

And frequency is quite important for sample ports from other sources (for example PC, samplers, etc). Also inability to provide correct sample rate prevent possibility to properly play audio in sync with video in many cases as commonly available sample rate converters can't properly support Amiga sample rates.
Musicians probably will appreciate this, perhaps it could trigger some revive of Amiga in musical scene but... But this is beyond this thread so from my perspective also EOT.

btw - never said that UART FIFO is unimportant (and HD MFM could be implemented without introducing new DMA slots), adding ADPCM decoder to Paula will made possible 16 bit and twice higher sample rate (when compared to OCS), ADPCM is used in Amiga scene (some demos using quasi standard created by Kalms), adding ADPCM encoder to Blitter could create nice tandem. But seem this is also EOT.

Forgot to add that FDD HD media require higher write current and slightly different precompensation and that's why FDD HD drive detect such floppy so it can switch to optimal settings. Using HD floppy in DD drive may lead to suboptimal results.
Personally never experienced issues with HD floppies on PC when good quality media was in use - even weird PC formats like DMF or 2M was fine.

[nonarkitten]

Originally Posted by pandy71

-->short
This is a bit contradictory but "not my circus and not my monkeys" so from my perspective EOT.

EOT?

Originally Posted by pandy71

-->long
Paula is very similar in terms of capabilities to the first Fairlight CMI, beside to this Amiga was used also as serious music machine/audio source... Studio quality definition then is quite vague...

Agreed, Amigas are still used by some DJs for its unique sound and versatility. Certainly it's "professional", but I think precisely, it was never designed with Red Book compatibility in mind. Though PAL is in-spec.

Originally Posted by pandy71

And frequency is quite important for sample ports from other sources (for example PC, samplers, etc). Also inability to provide correct sample rate prevent possibility to properly play audio in sync with video in many cases as commonly available sample rate converters can't properly support Amiga sample rates.

Sorry, but to me this whole paragraph sounds like nonsense. What on earth are you talking about? What use case is there for syncing a 44.1kHz audio stream perfectly with video? How is a 0.1% (0.2% on NTSC) error significant in 1/24th of a second? Why should Amiga be fixed to accommodate PC formats but break its own?

Originally Posted by pandy71

Musicians probably will appreciate this, perhaps it could trigger some revive of Amiga in musical scene but... But this is beyond this thread so from my perspective also EOT.

LOL. Why? Amiga is an instrument. It has a sound to its own. Attempting to change that, or "fix it" is misguided at best. No musician cares about Amiga's "limited" sample rates.

Originally Posted by pandy71

btw - never said that UART FIFO is unimportant (and HD MFM could be implemented without introducing new DMA slots), adding ADPCM decoder to Paula will made possible 16 bit and twice higher sample rate (when compared to OCS), ADPCM is used in Amiga scene (some demos using quasi standard created by Kalms), adding ADPCM encoder to Blitter could create nice tandem. But seem this is also EOT.

The ADPCM algorithm may be used but not in hardware. Adding it benefits no one since no one is using ADPCM hardware. AHI is an option, but no AHI hardware is ADPCM based either and most AHI playback will use 8 or 16 bit samples.

Amiga has four DMA slots per line for DF0 to DF3. This limits each drive to 30kB/s. HD drives normally read at 60kB/s. Amiga HD has to cut the RPM in half to match the allowed DMA rate.

[robinsonb5]

Originally Posted by nonarkitten

Amiga has four DMA slots per line for DF0 to DF3. This limits each drive to 30kB/s. HD drives normally read at 60kB/s. Amiga HD has to cut the RPM in half to match the allowed DMA rate.

I think what pandy71's suggesting is that if the Paula-replacement had a mode in which it could do MFM encoding itself, rather than leaving the CPU to do it, then you only have half as much data to transmit via DMA - and thus HD becomes possible using the existing DMA timings?

[nonarkitten]

Originally Posted by robinsonb5

I think what pandy71's suggesting is that if the Paula-replacement had a mode in which it could do MFM encoding itself, rather than leaving the CPU to do it, then you only have half as much data to transmit via DMA - and thus HD becomes possible using the existing DMA timings?

How would this work without completely rewriting Trackdisk? How would this work with custom track loaders? And how is this better than just having 2x Floppy DMA?

[robinsonb5]

Originally Posted by nonarkitten

How would this work without completely rewriting Trackdisk? How would this work with custom track loaders? And how is this better than just having 2x Floppy DMA?

Well obviously it would require a custom device driver, and obviously double speed DMA is the better solution - I was merely trying to bridge an obvious communication gap.

[QuikSanz]

It seems to me that with all of these chip improvements, a graphics card response should be a bit quicker. Does it work this way?

[QuikSanz]

And while I'm thinking of it. I have 4 meg of Zorro2 space to spare, if I get a Willow and Xander what is the best way, 2 meg each or 4 meg only on one or the other?

Chris

[nonarkitten]

Originally Posted by QuikSanz

It seems to me that with all of these chip improvements, a graphics card response should be a bit quicker. Does it work this way?

It wouldn't be hard to omit the extra wait states on Zorro access (or clockport) with Xander, but I can't guarantee that all cards would be able to operate that fast. Might work with a decent accelerator though. Other than that, there's not much that would make RTG a lot faster.

[QuikSanz]

It's a Picasso IV and a G-Force 030 Accelerator.

Chris

[QuikSanz]

Since I never got an answer on this, I will restate it.
On an ECS machine If I get Willow and Xander, will they auto allocate the 2Meg chip automatically or does all of this need to be programmed?
Maybe I need to wait till it's done and it all shakes out in the end

Chris

[simon_m74]

I NEED!!!!!
Count me in on 1 or 3

[nonarkitten]

Originally Posted by QuikSanz

Since I never got an answer on this, I will restate it.
On an ECS machine If I get Willow and Xander, will they auto allocate the 2Meg chip automatically or does all of this need to be programmed?
Maybe I need to wait till it's done and it all shakes out in the end

Chris

Yes, that's the plan. If you want more than 2MB, then that's more complicninded.

[QuikSanz]

So Willows memory is in the the Chip and is taken care of by it and not assigned to Zorro2?

Chris

[nonarkitten]

Originally Posted by QuikSanz

So Willows memory is in the the Chip and is taken care of by it and not assigned to Zorro2?

Chris

The 2MB of chip will always be detected by a reasonably up to date version of AmigaOS. This is always the case. Xander will automagically feed Agnus the missing high bits.

Memory above 2MB will need autoconfig I think, which means Xander will only allocate it if it's not being needed by something else. This could be difficult and it might be easier to either require the use of AddMem or a custom image loaded onto Xander or something like that.

To me, the best 2000 would be 4MB chip, 4MB of RTG and put all the fast RAM on the CPU accelerator. Like Buffee with 512MB in the 32-bit memory space. Chip immediately above 2MB is nice for WHDload for the same reason RTG memory is nice. Beyond 4MB is getting difficult to justify though.

[QuikSanz]

That clears it up a bit. Will wait till it's done to see. Thank you.

Chris

[pandy71]

Originally Posted by robinsonb5

Well obviously it would require a custom device driver, and obviously double speed DMA is the better solution

Any new feature will require driver, this is unavoidable...
Obviously more DMA slots (faster bus) is best solution but it will prevent possibility to mix for example new-Paula and original chipset...

Btw
There was solution (forget name of company) to use HD floppy drive with Paula - dongle with DRAM FIFO (+glue logic) so normal 300 rpm HD drive can work with Paula. Workaround, speed same as in DD FDD but it worked OK.

Originally Posted by robinsonb5

I was merely trying to bridge an obvious communication gap.

Appreciate your effort.

[QuikSanz]

I believe your thinking of the Catweasel.

Chris

[Bruce Abbott]

Originally Posted by pandy71

Btw
There was solution (forget name of company) to use HD floppy drive with Paula - dongle with DRAM FIFO (+glue logic) so normal 300 rpm HD drive can work with Paula. Workaround, speed same as in DD FDD but it worked OK.

That was the Power Computing XL 1.76MB high-density floppy drive.

Review by Paul Toyne in Feb 1994

LIST PRICE

XL Internal: 75 UK pounds + P&P
XL External: 85 UK pounds + P&P.

SPECIAL HARDWARE AND SOFTWARE REQUIREMENTS

HARDWARE

Any Amiga computer (external version).
Amiga 500, 600, or 1200 (internal version).

The XL drive is the size of a normal (PC880B) external drive and
doesn't have any vents, etc., for you to spill drinks through. It features
a disable switch and a through port. If the patch isn't run, the drive can
read/write 880K Amiga disks, 720K PC disks (with appropriate driver
software), but can only read Amiga 1.76MB disks. Once the patch is run, the
drive can also write Amiga 1.76MB disks, and can read/write PC 1.44MB disks
(using appropriate driver software).

In use, it is faster than the internal drive in the A4000.

Photos of the interface board

[utri007]

Are these going to get sale some day? If so where and by who? These are open sourced?