5V PAL or GAL with CMOS Outputs - Page 1
Forum section: electronics / beginners

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: August 21, 2016, 02:10:19 am
content: Fellow Tinkerers,I am restoring some vintage equipment and I am in a dire need of some 5V Programmable Logic Devices (PALs, PLAs, GALs) in DIP packages, that have CMOS levels compatible outputs. None of that TTL VOH= 2.4V rubbish !Does anyone know part numbers of any old PLDs, that have 5V CMOS compatible outputs withVOH> 3.5V ?They can be obsolete devices...

author: edavid
author_rank: Super Contributor
timestamp: August 21, 2016, 04:18:03 am
content: PALCE16V8Z/20V8Z/22V8Z have CMOS output, although it's not very well specified.

author: basinstreetdesign
author_rank: Frequent Contributor
timestamp: August 21, 2016, 04:46:51 am
content: Perusing a few of the ones on Digi-Keys website and looking at datasheets there seem to be quite a few that will go high within 0.2 or 0.3V of VCC as long as the output current is LE 100 uA.Otherwise if you need to supply a bit more current, then hanging a pullup resistor on the output will do it. It should be at least a few hundred Ohms up to a couple K.The only other option is more silicon in the form of a buffer or a transistor.

author: Zero999
author_rank: Super Contributor
timestamp: August 21, 2016, 10:45:24 am
content: Yes, a pull-up resistor would help it to reach +V but beware it would also mean it will compromise the output's ability to reach 0V.A 74HCT logic IC (e.g. 74HCT244, 74HCT125, 74HCT14 etc.) can be used as a level shifter to translate from 3V to 5V.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: August 21, 2016, 11:23:30 am
content: Quote from: edavid on August 21, 2016, 04:18:03 amHow so?Thedatasheetclearly states min VOH= 2.4V

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: August 21, 2016, 11:37:54 am
content: Quote from: basinstreetdesign on August 21, 2016, 04:46:51 amThe outputs of this PLD drive 74HC inputs so the DC current is minimal but the AC current is significant at 20MHz.Which parts list non-TTL VOH?Quote from: basinstreetdesign on August 21, 2016, 04:46:51 amAdding more components to support a PLD chip kind of defeats the purpose of using a PLD chip.Anyway, this is a restoration project that has to look "original". I can't have someone look and see a budge-job with bunch of hot pull-up resistors.

author: edavid
author_rank: Super Contributor
timestamp: August 21, 2016, 03:46:38 pm
content: Quote from: GonzoTheGreat on August 21, 2016, 11:23:30 amThat is the wrong datasheet. It's only the Z suffix "zero power" family that has CMOS output. (The other PALCE parts and GAL parts appear to have NMOS output, although that seems very odd for the GAL Z series, which is supposed to be a replacement for the PALCE Z series.)Here's the correct datasheet:http://latticesemi.com/~/media/LatticeSemi/Documents/DataSheets/PAL/PALCE22V10PALCE22V10ZDataSheet.PDF?la=enSee page 30 and page 22.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: August 22, 2016, 03:44:11 am
content: Quote from: edavid on August 21, 2016, 03:46:38 pmThanks for directing my attention to the "Z" suffix !I think, I will use these devices because my local supplier has them.Also, someone else has suggested this device:QuoteQuote from: edavid on August 21, 2016, 03:46:38 pmIndeed it is odd@OthersAny other PALs or GALs out there with true rail-to-rail CMOS outputs?

author: danadak
author_rank: Super Contributor
timestamp: August 22, 2016, 08:43:30 am
content: One possibility is to use a CYPRESS PSOC 5LP, it has a fabric thatis routable, tool has logic primitives (see attached) that are dragand drop in a GUI tool, and can also be programmed in Verilog.Only issue no DIPS, you would have to build an adapter board.Is CMOS R-R I/O, and has programmable pull up/dwn on I/O pins.Has ARM core if you need it, but you don't have to use it. But could beused for startup control, and rest of analog stuff (A/D, D/A, OpAmp, Vref,....) for other tasks.Regards, Dana.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 11, 2016, 10:34:07 am
content: So I bought several of these AMD PALCE22V10Z chips but now I have a problem with programming them.I cannot find theprogramming algorithmto build my own programmer and the Supported Devices List of a commercial programmer, that I have (the ChineseTOP2011), does not list the chips with the "Z" suffix and another programmer, I have (theTL866), does not even have the AMD PALCE chips on its Supported Device List.Why is the programming algorithm not available on the Internet after so many years?What to do?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 11, 2016, 10:56:28 am
content: Quote from: GonzoTheGreat on October 11, 2016, 10:34:07 amPLD programming specs were generally very hard to come by back in the day - I think because manufacturers were worried that incorrect programming would impact performance and cause support issues. This probably started when PALs used physical fuses, where it was important to get the waveform right.Flash devices are much less critical, and I think it's quite likely that programming is the same for different variants of similar devices, so would be worth trying the programmer you have on the Z devices - from memory Z iwas a variant to reduce standby power draw.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 11, 2016, 11:20:02 am
content: Quote from: mikeselectricstuff on October 11, 2016, 10:56:28 amBut today this should not matter to the manufacturer, since these chips have not been produced by them for years.I though that Internet does not forget anything.Quote from: mikeselectricstuff on October 11, 2016, 10:56:28 amMost importantly, chips with the "Z" suffix operate on the CMOS logic levels, which means that they require much more than the 2.4V to register a HIGH logic level with a 5V power supply.

author: Andy Watson
author_rank: Super Contributor
timestamp: October 11, 2016, 11:30:43 am
content: Quote from: GonzoTheGreat on October 11, 2016, 11:20:02 amAs Mike said, the manufacturers were (for some reason?) very guarded about releasing the programming information. So it never made it on to the internet.The datasheet suggests that the programming for the "Z" series is the same as the standard series - you will probably have to take a gamble and try the programming algorithms for a standard 22V10. I have a vague memory that Elektor published a description of the algorithm many, many years ago - I'll see if I can find the magazine - but don't hold your breath!

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 11, 2016, 11:40:20 am
content: Quote from: Andy Watson on October 11, 2016, 11:30:43 amThere is something very evil about that...or unethical at least.There have been successful lawsuits about manufacturers not releasing complete VCR programming instructions, so why none for the PLD chips which cannot be even partially used without programming?

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 11, 2016, 12:27:25 pm
content: Quote from: Andy Watson on October 11, 2016, 11:30:43 amRight after I reverse engineer the command set for that TOP2011 programmer and patch its software to output CMOS logic levels instead of the TTL levels for the non-"Z" PALCE chips....or make an external TTL-->CMOS level converter, once I figure out which input pins need this conversion. It certainly would not be all of them....

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 11, 2016, 12:27:56 pm
content: Quote from: GonzoTheGreat on October 11, 2016, 11:40:20 amSimple - people were expected to use a commercial programmer. Nothing unethical about that.Remember in those days, hobbyists weren't using these things to any significant extent.The design software ( e.g. CUPL) was expensive ( from memory over GBP1K) .Why would manufacturers go to the hassle of documenting and supporting programming specs when they could just deal with a handful of programmer manufacturers, and change the specs whenever they wanted if it allowed improved performance for a new part.

author: GonzoTheGreat
author_rank: Regular Contributor
timestamp: October 11, 2016, 12:38:15 pm
content: Quote from: mikeselectricstuff on October 11, 2016, 12:27:56 pmYes there is, because it creates aracketdesigned to extort money from the end users, while a cheaper solution exists and is purposely withheld.Would you feel it was ethical if a VCR manufacturer offered to send you a $500/h serviceman to program your VCR ?...and a VCR can be at least partially used without programming.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 11, 2016, 01:08:37 pm
content: Quote from: GonzoTheGreat on October 11, 2016, 12:38:15 pmThe VCR analogy is meaningless as it's a totally different market.The purpose was to ensure customers had a reliable way to use their parts.Most of the customers would be commercial places with the budget to pay for it, for whom making their own programmer would have cost more than buying one.It would make no business sense for them to support random DIYers lashing up their own soluitons. Remember this was a fast moving competitive market at the time.I have no idea how hard it was at the time to get programming specs - there were certainly a significiant number of programmer manufacturers so couldn't have been that hard once you'd convinced them you knew what you were doing.

author: edavid
author_rank: Super Contributor
timestamp: October 11, 2016, 03:23:32 pm
content: Quote from: GonzoTheGreat on October 11, 2016, 12:27:25 pmIt is quite likely that the programmer always puts CMOS logic levels on its output pins during programming. There's no reason not to. Hook up your scope and see.If not, you would just have to add pullup resistors, not level converters.