Atmel and Xilinx CPLD's

[Don]

As promised, here is what I know about Atmel and Xilinx CPLD's.
Please remember that your mileage may very so take what you need and
leave what you don't need. At this point I am not an expert with
either of these CPLD families but I am learning. I have however been
working with the small GAL and PAL type devices for about 20 years. I
also have some experience with the old AMD MACH series of CPLD's. Now
on to the subject at hand.

Xilinx

Of interest to this group would be the XC9536, XC9572 & XC95108. These
parts have 36, 72 & 108 macro-cells respectively. They come in a
variety of package types but the 44 & 84 pin PLCC (or J-lead) package
would be best suited for the hobbyist as they will fit in a through
hole solder tail PLCC socket.

Xilinx offers their WebPacks as a free download. All that is needed is
to register to get the download. The most current version only works
with Windows XP. However, If you study the download page you will find
a link to versions all the way back to 3.xx. Versions 4.xx and 5.xx
should work with Windows 98. I don't know if the later versions will
work with Windows 98 or not. I use Version 4.3 and it works fine with
Windows 98.

You will need to build your own programming adaptor and a schematic is
included in the documentation. It's a very simple circuit that
connects to the parallel port.

All of the Xilinx parts are available through DIGI-KEY.

Atmel

Of interest to the group would be the ATF1502, ATF1504 & ATF1508. These
parts have 32, 64 & 128 macro-cells respectively. They come in a
variety of package types but the 44, 68 & 84 pin PLCC (or J-lead)
package would be best suited for the hobbyist as they will fit in a
through hole solder tail PLCC socket.

Atmel offers their WinCUPL PLD compiler for free. You will need to
register to get the serial number. Atmel also offers a package called
ProChip Designer. This is a special version of the Protel (Altium) 99SE
package. You can down load a 30-day trial package to experiment with.
The retail price of this package is $150, I think. However, there is a
legal way to get it for free.

Atmel sells a development kit for $99. The part number is ATF15xx-DK2.
This is a complete kit with everything you need to get started.
Included in the kit is a request form for a FREE unlimited license for
ProChip Designer. The kit comes with an adaptor for the 84-pin PLCC
parts as well as two sample ATF1508 CPLD's. The adaptors for the 44 &
68 pin PLCC parts are $35 each.

About the free license. I didn't think I stood a chance in hell of
getting a free license but an email to the sales representative
convinced to give it a try. I told them I was retired and a hobbyist
and gave them a little sales hype and sure enough I got my free license
the next day. I guess they figure that if you spent $99 for the kit
that you also buy the other programming adaptors and some parts so what
the heck. The software is already on the CD-ROM and it doesn't cost
them a dime to send you a number anyway.

All of the Atmel parts and the development kit are available through
DIGI-KEY.

[ziggy]

Post by Don
As promised, here is what I know about Atmel and Xilinx CPLD's.
Please remember that your mileage may very so take what you need and
leave what you don't need. At this point I am not an expert with
either of these CPLD families but I am learning. I have however been
working with the small GAL and PAL type devices for about 20 years. I
also have some experience with the old AMD MACH series of CPLD's. Now
on to the subject at hand.

I still have not figured out how to relate gates to cells..

Everyone seems to use their own naming conventions which makes it hard
to compare their products.

1M gates sounds great on an Xilinx, but its such an arbitrary concept.

And what is a Atmel cell? In practical terms..

And then you have Altera....

/me shakes his head

I'm still holding off getting my development board until i get a handle
on it all. Digiliant has a great 1M xilinx board with ports, for $150
ish.

[Don]

Post by ziggy

Post by Don
As promised, here is what I know about Atmel and Xilinx CPLD's.
Please remember that your mileage may very so take what you need and
leave what you don't need. At this point I am not an expert with
either of these CPLD families but I am learning. I have however been
working with the small GAL and PAL type devices for about 20 years. I
also have some experience with the old AMD MACH series of CPLD's. Now
on to the subject at hand.

I still have not figured out how to relate gates to cells..
Everyone seems to use their own naming conventions which makes it hard
to compare their products.
1M gates sounds great on an Xilinx, but its such an arbitrary concept.
And what is a Atmel cell? In practical terms..
And then you have Altera....
/me shakes his head
I'm still holding off getting my development board until i get a handle
on it all. Digiliant has a great 1M xilinx board with ports, for $150
ish.

All PLD's or CPLD's, be they Altera, Atmel, Lattice, Xilinx,
Cypress or what have you us a "Macro-cell" as the basic building
block. They are all basically the same regardless of manufacturer. Each
one has it own "features" that they believe sets them apart from
the others. A detailed discussion of how a macro-cell works is beyond
what I could write in this news group. The best thing to do is to
download the data sheets for the part numbers I mentioned in the
initial message and do some studying.

As far as the number of gates is concerned, it's more important to
know how the gates are allocated rather than the number of gates. If
you divide the number of gates by the number of I/O pins you get a
rough idea of how many gates are allocated to each macro-cell (I/O
pin). Some logic families allow gate sharing between I/O micro-cells.
If one output requires a lot of gates they are taken from another
macro-cell that isn't being used or only requires a few gates. This
keeps the gate count and power consumption down to a minimum.

I only talked about Xilinx and Atmel in my original message because
these parts are readily available and the development tools are free.
Altera, Lattice and Cypress are also good parts but you need to buy the
development tools. My feeling is this; if I'm going to buy a
company's parts don't add insult by making me buy the development
tools also. If I want to buy the tools I will if I think I need them
but don't force me to just to use the parts.

Learning PLD's and CPLD's isn't something you can learn in a
couple of evenings. You will need to work with the various development
tools and do a lot of experimenting. With that said, if your willing to
spend the time you will find it a lot easier to build microprocessor
and micro-controller circuits. You will gain a new application for the
technology when you find, as I have found all too many times, that I
need to make a design change for one reason or another. With discrete
TTL logic it means a lot of rip up and re-wire. With a CPLD you just
need to change the design and re-program the part.

Don