Agnus and Denise Rebuild

[amigadave]

biggun wrote:

trekiej wrote:
If Agnus and Denise were remade to be chunky instead of planar, what other conversions would have to be made?
 

An Amiga chipset which is compatible with Planar/Chunky & Truecolor formats?
Sounds like this Amiga:
http://www.natami.net/specification.htm

EXACTLY!

I would love to see the whole Amiga community get behind the Natami project and other projects like it that will likely be created in the near future.

[trekiej]

One thing I would like to do with a new Denise and DAC is allow my Amiga 500 to work with 31.5khz without a flicker fixer.  How internal timing would be affected is beyond me.

The next is a chunky mode for better speed.

I wonder if a reworked paula could mean 1.44 mb pc floppy drives.

If Natami could become some replacement chip for older machines or even a replacement  board it would be fine with me too.
Here is a crazy idea, replace the Kickstart with Aros Kick. and redo the Denise.  I do not know how that will turn out :-D

[Zac67]

Forget about upgrading the A500 chipset - it lacks bandwidth badly. Implementing an 8 bit planar and/or chunky mode would eat up ALL chipset bandwidth during scanline DMA. Plus, it would probably also need an Agnus rework to enable the bitplane DMA.

A reworked Paula could in theory support HD floppy disks (1.76 MB for Amiga format) - but you'd have to rework DMA scheduling in Agnus since the allocated DMA slots are not enough for HD bandwidth (would probably screw up Agnus timing completely, that's why C= went the 'half speed' way).

You're surely much better off with Natami since it improves the whole design, not just single aspects.

[trekiej]

Natami it is then.

[billt]

Why remove planar? If you're going to make a new chip, why not add chunky to planar and have them both?

[trekiej]

@ zac67:
I wonder if a 1200 or 4000 be a better target then.  I could look it up but off the top of my head think that they would have 32 bit busses.

[bloodline]

trekiej wrote:
@ zac67:
I wonder if a 1200 or 4000 be a better target then.  I could look it up but off the top of my head think that they would have 32 bit busses.

The Amiga was always a "value" design... it pretty much was designed to be no more powerful than it needed to be... altering any part of the design would have a negative impact on the rest of the system... In terms of Busses the Amiga has always be deficient.

[AeroMan]

shoggoth wrote:

One guess could be that it's a very cheap solution. If I understand it correctly, it's basically a FIFO thing - you write 8 longwords of chunky data, which when read back becomes 8 longwords of planar data. No changes of the original chipset was required. Naturally, a "real" chunky mode would have been more efficien, but all and all it's not a bad solution considering the circumstances.

Makes sense... It`s a cheap chip  :-)

[trekiej]

In the spirit of South Park.  PeeCee's are bad M'kay.

[Fats]

bloodline wrote:

In terms of Busses the Amiga has always be deficient.

Not totally true. Zorro II did shine in the land of ISA.

Staf.

[Zac67]

Indeed. And Zorro III was way better than EISA in any respect - PCI didn't exist yet.

[trekiej]

Zorro being autoconfig made the Amiga a Cadillac in its day.