Quote:
Originally Posted by Gorf
How so?
Ist would take exactly the same silicon area as the transistor count would be more or less the same.
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Not as you already said - not all 4096 colors in YUV space can be displayed in RGB and at some point you need to prevent such situation.
Of course you can rely on external analog circuitry but analog is more expensive than digital...
Quote:
Originally Posted by Gorf
Again: how so?
In my account it would be the same or even lower transistor count and better sound quality.
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Not if you wish to keep same functionality as present in Paula with same number of pins... And how it can provide higher audio quality (DS sigma DAC's are not better than good monolithic DAC's - they are just cheaper)
Once again - more or less your ideas are corrected but they cost silicone - yuo need DSP-like features and plenty of multiplications that cost very serious amount of transistors.
Quote:
Originally Posted by Gorf
we are talking about "day one" = mid 80s.
Mary was mid 90s
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But it was picture how Commodore thinks as such 16 bit audio was one of important things to do in enhanced chipset but limitation was not DAC but DMA
Quote:
Originally Posted by Gorf
Again: you give absolutely no reason, why this should be the case ...
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this is simple - your volume regulation need to be sampled 64 times faster than sample rate of your audio samples, in case of 8 bit this 256 times faster i.e. your clock must faster 4 times... currently 3.58MHz and 6 bit PWM produce 55ksps maximum with volume control.
Quote:
Originally Posted by Gorf
sure - I just pointed out how it could be done better...
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partially, in theory you could do something similar as it was done in SID - use 8 bit DS DAC to feed bitstream to 8 bit multiplying DAC but this mean different state machine for Paula and maybe higher quality of audio. This could be done since day 1 different - not necessarily better.
Quote:
Originally Posted by Gorf
the same DMA the the DMAC in the Zorro2 hard disk controller provided (16bit) ... or the SuperDMAC in the A3000 (were it is 32bit obviously ...)
Or the ACSI DMA chip in the Atari ST for that matter...
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nope, not in A1000 and same - shared RAM between CPU and graphics (UMA), yes it can be done if you have faster RAM. In fact modern chipsets with embedded graphics suffer from same limitations only RAM interfaces are way more faster - but if you need really high graphic performance you are going for separate graphic card with local RAM and wide bus
Quote:
Originally Posted by Gorf
It would "steal" cycles from the CPU for sound, serial, parallel, MIDI and floppy (and potentially hard disk). For all usual use-cases this would be "neutral" speed wise, since it frees the cpu from several interrupts ... and of course floppy and sound would no longer be fixed to the horizontal frequency ...
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Hires and 4BPL already steal all CPU cycles i.e. RAM bandwidth is eaten by non CPU related cycles - you can have more DMA slots only if you reduce RAM cycle.
Quote:
Originally Posted by Gorf
You can do it quite simple and maybe a little bit crude, but with very few logic elements ... and still end up with a much better SNR as Paula does.
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Cost of packaging is more important than SNR... and Paula SNR can be improved by proper PCB layout and better decoupling + higher quality power.
Issue is that knowhow exist now (perhaps since 2000) - before it was not so obvious.
Rules for signal integrity on PCB in 2020 since 1985 also definitely improved.