Sold The new PLA substitute - PLAnkton, the new batch is here!
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I guess you liked them... Sending PM!
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PM reply sent!
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Payments received from chromo and Wes256.
Thank you for your support guys!
Thank you for your support guys!
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aphexian
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Greetings all,
I've been using these PLAnkton chips since they were first released. I have tested all of the other available PLA replacements available from EPROM style units, PLAtinum, Mega PLA, Super PLA, etc. and I have come to really believe in these chips. I use one in my fully socketed C64 chip testing board as well, since it is highly compatible with mixed and matched chips from NMOS to HMOS. This particular PLAnkton has been subjected to some harsh abuse and accidents as well and still functions flawlessly to this day. I've mistakenly installed it into the SID socket, installed it upside down in the PLA socket and handled it without any regard for ESD whatsoever and likely thousands of removals and reinsertions and it doesn't seem to care. After testing PLAnkton in nearly every style of C64 and SX64 ever made (besides shortboards obviously) they always just work; and for that I thank Eslapion and e5frog. Just thought I'd share with you all how impressed I've been with these little chips. Take care all.
-aphexian
I've been using these PLAnkton chips since they were first released. I have tested all of the other available PLA replacements available from EPROM style units, PLAtinum, Mega PLA, Super PLA, etc. and I have come to really believe in these chips. I use one in my fully socketed C64 chip testing board as well, since it is highly compatible with mixed and matched chips from NMOS to HMOS. This particular PLAnkton has been subjected to some harsh abuse and accidents as well and still functions flawlessly to this day. I've mistakenly installed it into the SID socket, installed it upside down in the PLA socket and handled it without any regard for ESD whatsoever and likely thousands of removals and reinsertions and it doesn't seem to care. After testing PLAnkton in nearly every style of C64 and SX64 ever made (besides shortboards obviously) they always just work; and for that I thank Eslapion and e5frog. Just thought I'd share with you all how impressed I've been with these little chips. Take care all.
-aphexian
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Deleted member 14264
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Woa!! I'm glad this particular unit survived all the harsh conditions it was exposed to - the SID socket will have subjected it to 12Vdc !!! - but please people, don't take this as an open invitation to torture my little babies
I'm happy you like them.
Thanks for the comment. We're close to 700 units sold and presently developing other products.
Perhaps your plan is to slowly replace all ICs in the C64 one by one with modern variants?
The CPU and TED in the C16 and Plus/4 would be very nice to have replacements for, although I know that would be a much bigger undertaking than a PLA/8701 replacement..
Making the PLAnkton compatible with other machines (perhaps configurable with jumpers like on SuperPLA) would also be a very nice addition.
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I may be able to make a substitute for the CPU used in the C16 and Plus/4 but there isn't much of a demand for that. It's really just a 6502 with the addition of a small IO bus, just like the 6510/8500 in the C64.Perhaps your plan is to slowly replace all ICs in the C64 one by one with modern variants?
The CPU and TED in the C16 and Plus/4 would be very nice to have replacements for, although I know that would be a much bigger undertaking than a PLA/8701 replacement..
Making the PLAnkton compatible with other machines (perhaps configurable with jumpers like on SuperPLA) would also be a very nice addition.
The TED, however, is a whole different ball game; it's a custom chip with both digital and analog functions. To give you a point of reference, the VIC-I chip used in the VIC-20 has been closely examined and partly documented on the Denial forum and after hundreds of hours of investigation, less than 10% of it was detailed by lance.ewing. I did a small part by sharing a few dozens of scope captures from the video signal. The TED is at least double the level of complexity of the VIC-I.
I created a project to make clones of the 6526 CIA used in the C64, C128 and 1571 disk drive. The result was a product I would have had to sell for more than 20$US per unit and presents strictly no advantage over the improved 8521. These chips sell for about 5-6$ each and are widely available.
The bottom line is, it's not really practical, even if it was possible, to replace all ICs of a Commodore computer with modern equivalents.
This being said, I am always actively looking for people interested in giving a hand with these projects.
It is also hard to find the 7501/8501 CPU but as you say it is 99.5% identical to a 6501 but still not directly compatible. Perhaps there would be a market for an adapter PCB so one could use a plain 6502 or 6510 instead? From what I read, it should be possible to add the missing funtionality using external logic? I know I would probably buy one or two of such adapter boards if they were available. I have a C16 with a dead CPU here.
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It is perfectly possible to make an adapter board fitted with a CPLD like the one found on PLAnkton and program it to provide the missing functionality to turn a 6502 into a 7501/8501. The question is, once again, it is practical to do so ?
Considering the time and cost of developing such an adapter, you need to be sure you'll sell at least one hundred of them before you even begin.I know I would probably buy one or two of such adapter boards if they were available. I have a C16 with a dead CPU here.
Selling one or two is far from enough to start the train rolling. The adapter itself, once developed, has a cost for components attached to it and this may turn out to be more than the price for a 7501 on eBay.
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Yes, I have not investigated it in any detail to judge the feasibility of such a product. I'm sure you have a much better idea about this.
Although the 7501/8501 CPU is somewhat hard to find, the market is probably also quite small. Certainly much smaller than a C64 PLA.
Although the 7501/8501 CPU is somewhat hard to find, the market is probably also quite small. Certainly much smaller than a C64 PLA.
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Well, the board needs to be the size of a DIP 40 chip and requires about the same components as PLAnkton plus a 40 pin socket so make that about double the price of a PLAnkton, plus a 6502. Would you be willing to pay that for your 8501 substitute?
This means the cost of development has to be spread across a much smaller number of sold units. You're now up to triple the price of a PLAnkton for your substitute.
3 x 14 Euros = 42 Euros - is that what you're willing to pay to get a replacement 8501 ?
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Well, I do have plenty of 6502s available already, but I'd probably think the price you estimate for the board on its own would be too high to make sense.
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... possible but not practical...
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