Posted Mon Jan 1, 2018 5:24 AM
I didn't check but if there are small form pure 6502s being made those four external chips required to make it a SALLY could easily be added in the smallest SMD cases they come in today and put on a PCB the size of the old DIL40.
I also haven't checked a lot about the SID replacement but this looks like a drop in replacement with DIL40 PCB size.
The true sad thing is that all of the dedicated Atari VLSI's apparently have a very good design, because the vast majority simply keeps going, way, way, waaaaayyyynbeyond their expected lifetime....I'm actually convinced most VLSIs die due to power supplies going bad and/or Commodore 64 power supplies being tried on A8's.
The Commodore designers weren't as good at designing reliable chips. History tells that they tried to get a video chip running when the 800 was already on the market for two years but they couldn't get it to work.
Their later working chips like the VIC-2 and SID run really hot and thus die a lot sooner than Atari's VLSIs.
There would be two ways to get replacement chips:
1) find the original films at one of the companies , (or deliver new ones that have been reverse engineered )that produced these chips for Atari and have them produced again. This will be very hard to get done for a good price nu it is not impossible. F.I. Certain DAC chips (Digital Analogue Converters) are still so popular that prices for them went up to about 27 dollars. The company who produced them in the 80s apparently noticed this, figured there was good money in this and restarted production. Guess at what price they sell them for (while there is zero development costs). Their bad luck is that the Chinese sell copies which work just as good and cost about 1,50'dollar.
Which would be another idea: if there are complete and 100% correct films in the hands of "us"....we would "only" need to find a Chinese factory........not impossible.....
2) FPGA. Very often I hear and read that a FPGA emulates another chip, or complete hardware. This is not true....it is equal to the original hardware. Emulation is a processor/computer mimicking another (old) computer or chip, but howevermfast, it is still,doing it step by step....an FPGA is direct, electrically exactly like the original. Anyway, it has been possible to create FPGA replacements for the A8 VLSIs for quite a long time already....but until now it was simply a lot cheaper to buy new old stock chips. I think for POKEY we are now getting the situation where the price of an FPGA replacement would be about the same as an original NOS one....so hopefully this will change the situation.
However....there are already FPGAs around (Eclaire)....one chip containing an entire A8. Imhave no experience with them yet, but I have owned two FGPA based arcade (Williams) PCBs. These still used an original separate processor....but everything else on the original PCBs (loads of standard TTL chips) was in FPGA and this worked absolutely 100% like the original boards.
So that's a great development...(and I'd love to see a portable A8 coming from this )....but I prefer to keep the original,hardware running for as long as possible, with as much as original,parts as possible because to me this is the charm of the hobby.....
You don't put a modern day engine in a 60's classic car....but if you need to use a replacement part if there simply are no original parts available anymore to keep that old engine running.....