Re: The Dos and Don'ts of using an EPROM as PLA in a C64.
Posted: Mon Jul 01, 2019 11:25 am
Hi eslapion and radron5809
This is where I got mine :
https://www.aliexpress.com/item/3270864 ... 17edd4kd9b
Here are some updated videos using the Motorola 27LS279 chip installed.
Knockoff (Fake) ST 27C512 - 90B1 (ST electornics never relaesed a ...B1 variant!)
Commodore Factory PLA
This is where I got mine :
https://www.aliexpress.com/item/3270864 ... 17edd4kd9b
I absolutely agree.eslapion wrote: ↑Mon Jul 01, 2019 10:16 am Using a 74LS279 as a means of detecting undesirable spurious logic lows from a PLA will allow you to tell for sure if a PLA has problems but the opposite is not true. If a PLA will not trigger the test schematic I have suggested then it MAY be a good PLA replacement but using an oscilloscope, as I did is the only way to be perfectly sure.
The Rigol DS1052E is probably one of the least expensive scope you can get which will do the job but there are many others that may be even less expensive.
Here are some updated videos using the Motorola 27LS279 chip installed.
Knockoff (Fake) ST 27C512 - 90B1 (ST electornics never relaesed a ...B1 variant!)
Commodore Factory PLA