CPLDs - which one to start with

[TomS_]

Hi all.

Im feeling like I want to break off into another project tangent at the moment, and CPLDs are all over my mind.

I have a bunch of ATF16V8's and 22V10's which Ive played around with a little and feel like Im getting to grips with CUPL (and WinCUPL and its oddities....)

So now Im looking towards the bigger brothers, something like the ATF150X series. It seems like these are preferred over the 2500 and 750 series parts?

So my question is: these devices still seem to be "current" and available at reasonable pricing and quantities from the usual suspects, so are they a worthwhile investment in development boards/programmers (e.g. ATF15XX-DK3-U), parts themselves, and time to learn how to drive them? Or can someone suggest a "better" vendor to learn instead (and elaborate why)?

I realise that last bit may be very subjective and application specific, but I guess Im just interested in obvious/hands down differences.

FWIW Im not looking to go straight to FPGAs just yet, but Im building my way up there, if you will.

Thanks!

[KrudyZ]

In my opinion there is no reason in 2019 to stick with CPLDs programmed in CUPL.
It's like programming in assembly language, useful to know how a processor does things, but very inefficient to actually getting anything done.
Small FPGAs are both a lot more capable and cheaper and are supported by modern tool sets.
You should really be spending your time learning Verilog or VHDL.
This would at least bring you up to the C language equivalent in hardware design.
For small projects, I like using MACHXO3 FPGAs from Lattice.
The tools are free and small designs synthesize and place and route in no time.

[TomS_]

I would go to FPGAs, but Im on a kind of retro-trek through the different eras of programmable logic. Im quite enjoying it. 

Atmel had some software called ProChip Designer which allows you to write VHDL/Verilog for this series of PLD, but they dont seem to provide licenses for the simulation tools any more. Perhaps that can be overcome with other tools.

Other reasons for looking at these devices in particular is they are easily available in "hand solder friendly" packages, e.g. TQFP, or PLCC which can be through hole socketed, hence they are still relatively hobbyist friendly. I havent looked in any great detail at FPGAs yet, but anything I looked to use I would want to be the same, and a lot of FPGAs are in not-so-friendly packages like BGA.

Other things to consider are working voltages. Im looking for something that operates off 5V, not just 5V tolerant IOs.

Its very much for the retro aspects than anything else at this point. I will get to FPGAs.

[Kjelt]

For small projects, I like using MACHXO3 FPGAs from Lattice.

Only BGA packages and >€10 a piece don't go into my hobbieist vocabulary 

[asmi]

Only BGA packages

BGA packages are great, and the sooner you start using and embracing them, the better your projects will be as you won't artificially limit your projects based on some outdated arbitrary metrics. 0.7 mm pitch and up BGA are absolutely doable by a hobbyist these days, as both affordable 4 layer PCBs service and basic reflow equipment are present.

>€10 a piece don't go into my hobbieist vocabulary 

Hmm - what?

[SiliconWizard]

Yeah the smaller MachXO3 are quite cheap. You can also take a look at the iCE40 series.

[Kjelt]

I checked at Farnell , big price difference 

[NorthGuy]

Other reasons for looking at these devices in particular is they are easily available in "hand solder friendly" packages, e.g. TQFP, or PLCC which can be through hole socketed, hence they are still relatively hobbyist friendly. I havent looked in any great detail at FPGAs yet, but anything I looked to use I would want to be the same, and a lot of FPGAs are in not-so-friendly packages like BGA.

TQFP, you must solder manually, then inspect for bridges, then remove the bridges, which is not fun with 0.4mm pitch TQFP.

BGA, you just apply flux, slap the BGA on top and heat. If BGA is small enough you can just use air gun. For bigger ones you can use an oven. Your only concern is to make sure that everything is flat. BGA is perfect for you if you only want to make one or two boards.

[KrudyZ]

Assuming this is for experimentation and not a product, you should just get an eval board that brings out all the pins to 0.1" headers.
Plug in the USB cable to power and program the thing and focus on what you actually want to do...

[TomS_]

BGA, you just apply flux, slap the BGA on top and heat. If BGA is small enough you can just use air gun. For bigger ones you can use an oven. Your only concern is to make sure that everything is flat. BGA is perfect for you if you only want to make one or two boards.

Is it necessary to use ENIG surface finish when using BGA packages, or can it be done with HASL?

I read some time ago that super flat surfaces are important for successful BGA reflow soldering, and ENIG is one such way to achieve that, but that typically boosts the cost of the boards by a generally non-trivial amount of money.

I don't particularly have anything against BGA, other than I will need to up my game a bit to be able to design and assemble the boards afterwards - I.e. I need to get a hot air gun at the very least. I figure I will get there eventually, just have to finish renovating the house first. 😋

[NorthGuy]

Is it necessary to use ENIG surface finish when using BGA packages, or can it be done with HASL?

I always thought that it was, but I haven't personally tried to mount a BGA on HASL surface. So, I don't have any experiences to back it up.

I read some time ago that super flat surfaces are important for successful BGA reflow soldering, and ENIG is one such way to achieve that, but that typically boosts the cost of the boards by a generally non-trivial amount of money.

It depends. If your board is already 4- or 6-layer, the PCB price has already increased for the reason that it is not 2-layer. After that, adding ENIG is not dramatic. Besides, prices are still falling.

[asmi]

I always thought that it was, but I haven't personally tried to mount a BGA on HASL surface. So, I don't have any experiences to back it up.

I have successfully used HASL boards with small BGAs (BGA-24 to be exact - QSPI flash chips), but now most BGA chips I use are FPGAs and so they are expensive enough for added price of ENIG to not matter too much

[jmelson]

Hi all.

Im feeling like I want to break off into another project tangent at the moment, and CPLDs are all over my mind.

I have a bunch of ATF16V8's and 22V10's which Ive played around with a little and feel like Im getting to grips with CUPL (and WinCUPL and its oddities....)

CUPL?  How 1980's!  Yes, as others have said, just move right to modern tools like VHDL or Verilog.  Take a look at Xilinx's 9500XL series, or the coolrunner II.  Quite inexpensive parts, available in reasonable packages.  Some of the smaller parts are $1 each in single quantity.
Only quirk I know of is the 9500XL has "weak keepers" on the inputs that interfere with doing analog-type things on the inputs, like oscillating bare quartz crystals or making one-shots on inputs.  Even then, there are ways to deal with them.

Jon

[iMo]

I did many boards with BGA48 on HASL (the BGA balls escaped on a single side, no vias), hand soldered with hot air. Yield 90%.

5V IO requirement - difficult with modern cpld/fpgas. Better do migrate to 3.3V, your life become much easier.

[TomS_]

Better do migrate to 3.3V, your life become much easier.

The 5V requirement comes from the kinds of projects I am working on. In this case more retro themed, think Z80 processors.

When I do more modern themed projects I am typically working at 3.3V.

[asmi]

The 5V requirement comes from the kinds of projects I am working on. In this case more retro themed, think Z80 processors.

You can use level converters - they are cheap and plenty fast for your needs. Also if my memory serves me, Z8L180 can work on 3.3 v just as well.

[Dmeads]

https://store.digilentinc.com/cmod-c2-breadboardable-coolrunner-ii-cpld-module/

i think digilent just came out with this board, but i think it only operates on 3.3V logic, not 5V.

Hope this helps

[Dmeads]

if you like the board, the cool runner cpld chips are available on digikey in TQFP and BGA for super cheap They are non-volatile and use free tools to program.
https://www.digikey.com/products/en/integrated-circuits-ics/embedded-cplds-complex-programmable-logic-devices/695?k=cool+runner&k=&pkeyword=cool+runner&sv=0&pv152=i64&sf=0&FV=ffe002b7%2Cffec2de2&quantity=&ColumnSort=0&page=1&pageSize=25

[technix]

Since you need 5V and have soldering woes, how about MAX7000S series? Those are native 5V parts and comes in PLCC and large-pin-pitch TQFP versions. You can go TQFP if you are okay with surface mounting, or if you want to through hole mount it you can use the PLCC version and add in a through hole PLCC socket. Socketing chips also allows you to replace them should you feel the need to. (It won't hurt to socket all your DIP and PLCC chips if you can.)

[Kjelt]

Since you need 5V and have soldering woes, how about MAX7000S series?

They look obsolete, very high price. Where did you see them for a normal price to advise them ?

[spudboy488]

The MAX3000 and MAX7000 series have been obsoleted by Altera. Microchip/Intel has a series that are pin compatible with some of them and are 5V.

https://www.digikey.com/products/en/integrated-circuits-ics/embedded-cplds-complex-programmable-logic-devices/695?k=&pkeyword=&sv=0&pv1339=9&pv1339=10&pv1339=11&sf=0&FV=ffe002b7%2Cfffc0096&quantity=&ColumnSort=0&page=1&stock=1&pageSize=25

[technix]

Since you need 5V and have soldering woes, how about MAX7000S series?

They look obsolete, very high price. Where did you see them for a normal price to advise them ?

They are obsolete and AFAIK those are the latest 5V tolerant CPLD in PLCC package. I found them on Taobao and the quality is questionable at best to be honest. I do speak Chinese allowing me to dispute them should it went wrong. If you don't trust Shenzhen markets or speak Chinese, it would be a better idea to migrate the entire design to a 3.3V or lower supply rail and use modern parts.

Hand soldering TQFP isn't that hard IMO - I do it often enough. For me it si BGA that is daunting and I try to avoid it as much as I can. Just tolerate solder bridges with you first apply solder to the joints, and clean them up later using a lot of flux and a clean iron tip. Ditto for QFN really.

[Canis Dirus Leidy]

Since you need 5V and have soldering woes, how about MAX7000S series?

They look obsolete, very high price. Where did you see them for a normal price to advise them ?

LCSC sells MAX300A (EPM3064ATC44-10N to be exact) for $2.5, without shipping.

P.S. According to documentation MAX II and MAX V can directly (external clamp diode and is enough) drive 5V TTL ICs.