PAL - a modern equivalent for combinational logic

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Having ploughed through the internet and any number of data sheets, I keep bouncing off the 16L8 currently supplied by Rochester Industries. https://www.digikey.co.uk/en/pro...

 

It looks as if a couple of those would free up a dozen or so other chips, but it looks like it was designed in the stone age: it works at nominal TTL voltages and eats the thick end of a hundred milliamps surprise.

 

What I'd really love is a similarly simple device, but using HC logic levels (so 2-6v power) and HC currents (so tens or hundreds of microamps) and in an ideal world in a SOIC package. If it only costs a quid or so that's even better...

 

I'm blowed if I can find such a thing. I suspect it's in the realm of 'things Mr Barnacle finds useful but nobody else does' along with my other pet peeve: parallel memory with a serial interface...

 

Any thoughts?

 

Neil

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Try a 16V8, or for more fun, a 22V10.  Programming them is a bit of a pain in SOIC - you need to find a ZIF SOIC socket to stick on your programmer.  Chips themselves are more like USD$2.20 or so.  S.

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barnacle wrote:
modern

laugh laugh laugh laugh 

 

I remember when these were new - it was back in the mid 80s.

 

IIRC, Monolithic Memories started them, later becoming AMD.

 

There was a thing called "PALASM" for creating the programming - it was provided as a source listing in the back of the databook.

I remember a poor apprentice got the task of typing it in...

 

Rochester make their living by supplying obsolete components - by buying-up old stock, and/or buying manufacturing rights.

 

EDIT

 

Apparently, Lattice now hold the "PAL" trademark: https://en.wikipedia.org/wiki/Programmable_Array_Logic

 

So maybe Lattice would be the people to ask ... ?

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Last Edited: Tue. Nov 23, 2021 - 10:34 AM
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22V10s are still being made (by Lattice Semi, among others), and come in several zillion varieties of low voltage, low power, cost, package, and high speed.  The programming language I use is ABEL(5).  Converting from PALASM (yes, I have a few of those lying around) is a matter of find'n'replace and a bit of wrapper tinkering.  VHDL or Verilog for a PAL strikes me as wacky overkill.  S.

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AT22V10 was actually the first Atmel product I used. :)

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Hmm. Thanks, possibilities there though I fear the current consumption may still be too high - I've not used them before but I'm assuming that they can be used in a straight combinational logic way?

 

Not sure about in-circuit programming, which would be nice; I'm always nervous about externally programming SM parts.

 

I'll investigate further.

 

Neil

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barnacle wrote:
, but using HC logic levels (so 2-6v power) and HC currents (so tens or hundreds of microamps) ...
GreenPAK | Dialog

 

"Dare to be naïve." - Buckminster Fuller

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awneil wrote:
So maybe Lattice would be the people to ask ... ?
Some Lattice FPGA have FOSS toolchains :

Icestorm | AVR Freaks

 

plus a few others :

SymbiFlow - the GCC of FPGAs

 

 

"Dare to be naïve." - Buckminster Fuller

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Hello,

 Programmable Array Logic chips were used to replace networks of TTL gates that decoded the addresses of the various sections of a microprocessor system.  Microcontrollers have these sections internally.

 

If the system that you are considering using PALs in is only a few megaHertz in system clock speed, consider using a 20MHz microcontroller to replace TTL chip logic networks.

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Scroungre wrote:
22V10s are still being made (by Lattice Semi, among others), and come in several zillion varieties of low voltage, low power, cost, package, and high speed. 

 

I don't think I'm reading the right datasheets - low power seems to be 25mA at best, which is way more than I'd like to use.

 

The GreenLab stuff is a little better but still not in the range I'd really like. Plus the difficulty of programming either... what's so hard about a 16v8 in HC with a straight-forward SPI to program it?

 

Neil

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https://www.dialog-semiconductor...
 

“Modern packages” too. :-(

 

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some low power logic...however they talk about static power

 

Ultra Low Power • 55 µA static power consumption, suitable for smartphones, tablets, mobile enterprise devices and other power sensitive applications

 

https://www.quicklogic.com/wp-co...

 

how about PEEL?

 

 

ready to ship

https://rcfreelance.com/p/ic/953...

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Last Edited: Tue. Nov 23, 2021 - 09:05 PM
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westfw wrote:
“Modern packages” too. :-(
... though sockets and/or PCBA for proof-of-concept and first prototype.

Purchase GreenPAK Parts and Development Tools | Dialog

 

"Dare to be naïve." - Buckminster Fuller

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barnacle wrote:

What I'd really love is a similarly simple device, but using HC logic levels (so 2-6v power) and HC currents (so tens or hundreds of microamps) and in an ideal world in a SOIC package. If it only costs a quid or so that's even better...

That's a combination that has been left behind by progress.

SPLD like 16L8, 16V8, 22V10 are not really designed for In System program. 

 

You can in system program the smaller CPLDs, like ATF1502ASL which is 5V and comes in PLCC44 and TQFP44,

or parts like LC4032 from lattice or XC2C32 from Xilinx, but those are 3v3 only. 

 

 

barnacle wrote:

Scroungre wrote:
22V10s are still being made (by Lattice Semi, among others), and come in several zillion varieties of low voltage, low power, cost, package, and high speed. 

I don't think I'm reading the right datasheets - low power seems to be 25mA at best, which is way more than I'd like to use.

There are ATF22V10CZ parts that need uA static, but their cost/logic is not great.

 

 

barnacle wrote:

The GreenLab stuff is a little better but still not in the range I'd really like. Plus the difficulty of programming either... what's so hard about a 16v8 in HC with a straight-forward SPI to program it?

 

You need to dig a little in the GreenPAK, most of their early parts are OTP, as their market is large volumes, but they are expanding.

 

The closest to what you want is their new EEPROM parts with i2c programming  SLG46824  &  SLG46826 - those come in TSSOP20, 2.5 ~ 5.0 Vcc  68c/100 Mouser has stock.

Or there is even a SLG46824V-DIP  SLG46824V GreenPAK Programmable Mixed Signal Matrix 20-Pin DIP Prototyping that is ~ $2

 

https://www.dialog-semiconductor...

 

 

GreenPAK are also expanding with this ForgeFPGA line in 2022

 

https://www.edacafe.com/nbc/arti...

 

https://www.dialog-semiconductor...

 

but I've not seen Vcc range info for ForgeFPGA yet, and I suspect it will be low supply and similar to Lattice iCE40 series in voltage/package/capability.

 

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“Modern packages” too. :-(

... though sockets and/or PCBA for proof-of-concept and first prototype.

Yeah; I have been impressed with their "prototyping tools", and they were close enough to "exactly what I was looking for" to buy a bunch of their first parts (back when they were Silego) (hobbyist-scale; like $150 worth of development kits, two parts, and some extra sockets.)  (alas, those parts are discontinued, and I haven't actually used them :-( It seems I'm rarely interested in things that go faster than microcontroller speed.)

 

I've always been a bit surprised that there isn't a tool for turning some low-end microcontroller(s) into a slowish PAL-replacement(s).  It should be pretty trivial, even to the point of being able to use existing PAL fuse files (binary or source)

"Propagation delay" would probably be well less than 5us.
(of course, if you can live with 5us delays, you enter the whole "why not have the micro do all the rest of the stuff too?" question.)

 

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barnacle wrote:

I've not used them before but I'm assuming that they can be used in a straight combinational logic way?

 

Yep.  In a 22V10 all registers are optional.  Note, however, there is variable width on the outbound OR gates, depending upon which pin you use.

 

barnacle wrote:

Not sure about in-circuit programming, which would be nice; I'm always nervous about externally programming SM parts.

 

Not enough pins, basically.  And not enough logic.  That's CPLD or FPGA territory.  And 22V10s are still made in DIP and PLCC (readily socketable - and with ZIF sockets for the programmer) forms.   S.

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Thank you all, folks!

 

Looks like there isn't anything that's exactly what I want, but some possibilities if I decide to go that way. For now I suspect I'll stick with my dozen or so basic logic chips - there will be three or four times that elsewhere in the circuit anyway (which will of course also be potentially subject to compression in a chip) - but what I want to do is make it obvious what the logic is doing. Old school, that's me in this context.

 

Neil

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Must admit I quit using discrete logic chips (with a few exceptions) in the 16[R/L][2/4/6/8/8] days (before the turn of the century), all in 20-pin DIPs.  A 24-pin 22V10 was a huge upgrade!  And they and the new 16V8s were reprogrammable!  No more throwing entire chipsets away!  Then off to XC9500s for even more powerful boards, but Xilinx quit making them, and I've really moved almost entirely into microcontrollers.  As wesfw pointed out, there's not very often a reason to go faster than that...  and the answer there is usually* "a faster MCU"  laugh   S.

 

* Yeah, for really wacko stuff there's FPGAs.  They're beastly fast, and can do things in weird bus widths (should you feel so inclined...).

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Simonetta wrote:

Hello,

 Programmable Array Logic chips were used to replace networks of TTL gates that decoded the addresses of the various sections of a microprocessor system.  Microcontrollers have these sections internally.

 

If the system that you are considering using PALs in is only a few megaHertz in system clock speed, consider using a 20MHz microcontroller to replace TTL chip logic networks.

 

Since the OP tried to replace the Micro's to complex TTL.The PAL sufficiently for the purpose.

 

In the Third world countries,The Micro's were the options.

 

barnacle wrote:
Not enough pins, basically.  And not enough logic.  That's CPLD or FPGA territory.

 

Yup,that's our lesson.

 

 

 

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Jeckson wrote:

barnacle wrote:

Not enough pins, basically.  And not enough logic.  That's CPLD or FPGA territory.

Yup,that's our lesson.

 

That was actually ME, replying to barnacle.    You may have gotten your nested quotations confused.  S.

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barnacle wrote:

Looks like there isn't anything that's exactly what I want, but some possibilities if I decide to go that way. For now I suspect I'll stick with my dozen or so basic logic chips - there will be three or four times that elsewhere in the circuit anyway (which will of course also be potentially subject to compression in a chip) - but what I want to do is make it obvious what the logic is doing. Old school, that's me in this context.

If you need the raw speed, direct logic is hard to beat. 

 

Keep in mind newer MCUs have Configurable Logic cells, which are simpler versions of the macrocells in a SPLD.

They can be useful for generating one-shot or sticky type HW signals to arm/capture/control counters and timers.

 

Cypress have CPLD level Logic blocks inside some of their PSOC parts, and those were wide supply (but generally larger packages).

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Who-me wrote:
Cypress have CPLD level Logic blocks inside some of their PSOC parts, ...
and GPIFTM in the USB device controllers.

CYUSB301X, CYUSB201X: EZ-USB® FX3: SuperSpeed USB Controller

 

"Dare to be naïve." - Buckminster Fuller

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Very high speed isn't critical but probably low megahertz... delays through the existing (inasmuch as it's simulated, but not yet designed using actual parts) are only three or four gates, so perhaps a handful o' nanoseconds.

 

I could use a fast processor (or indeed a prom - through the delays are greater) but that rather defeats the whole point of the idea which is to demonstrate how the logic works :) A PAL would be an acceptable simplification but the power requirements would cripple the design, sadly.

 

Neil

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If you really want to demonstrate logic, build a Babbage engine.  laugh  Static power consumption zero, dynamic power consumption limited by how hard you feel like cranking it!  Surface-mount, too - I recommend a thick concrete surface.  cheeky  S.

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Scroungre wrote:
If you really want to demonstrate logic, build a Babbage engine.  laugh  Static power consumption zero, dynamic power consumption limited by how hard you feel like cranking it!  Surface-mount, too - I recommend a thick concrete surface.  cheeky
 Some of US built counter with leds for demonstrated the logic,All variety’s of counter.Mostly at YouTube also..

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Scroungre wrote:

If you really want to demonstrate logic, build a Babbage engine.  laugh  Static power consumption zero, dynamic power consumption limited by how hard you feel like cranking it!  Surface-mount, too - I recommend a thick concrete surface.  cheeky  S.

 

Oh, I feel some of Konrad Zuse's early work is more accessible...

 

Neil

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barnacle wrote:
which is to demonstrate how the logic works :) A PAL would be an acceptable simplification
Still a "black box" ;-) 

 

I want to see it wired out in 74xx or 4xxx!

 

Actually, even that is "black box" let's have it in NPNs and PNPs (and indicative LEDs to show all the logic levels !)

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Norbit! 

#1 Hardware Problem? https://www.avrfreaks.net/forum/...

#2 Hardware Problem? Read AVR042.

#3 All grounds are not created equal

#4 Have you proved your chip is running at xxMHz?

#5 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand."

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barnacle wrote:
Oh, I feel some of Konrad Zuse's early work is more accessible...
Yup,consider the SBC with GPIOS..If you like the OpenZuse 11.0 DVD for Thanksgiving.Oldies but work in the past.

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Last Edited: Thu. Nov 25, 2021 - 01:28 PM
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Over the years, I have used the CoolRunner products (since before Philips sold the product line to Xilinx) in several projects for some discrete logic cleanup.

Not SOIC and the current is greater than you want, but I really like them and they are ISP.

 

It looks like Digi-Key has some in stock for $2.16 (USD).

David

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Brian Fairchild wrote:
Norbit! 

I remember them!

 

https://en.wikipedia.org/wiki/NORBIT

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Here you go, Cliff - one of the simpler bits, just six in and ten out... it controls the ALU operation and routing.

 

 

The more complicated bits aren't designed yet; at the moment I'm using a ROM to provide them but its fourteen bits in and sixty-four bits out (though I think that will reduce to about eighteen). I've just discovered a really subtle bug in Logisim-Evolution whereby a couple of bits errors occur in the ROM loading process, which is really doing my head in! https://github.com/logisim-evolu... Ive just discovered I'm an idiot...

 

Neil

 

Last Edited: Fri. Nov 26, 2021 - 07:33 PM
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Or another - the insides of a 74HC181 ALU. I need that to simulate it but I can at least buy them off the shelf :)

 

Neil