Altera EPLD

In a project I use the Altera EPM3256ATC144-10.
Now I have the necessity to make some changes to the project, but I don't 
have enough macrocells in the actual devices.
Alteras doesn't have a pin-to-pin compatible EPLD  with the EPM3256ATC144-10 
but with more macrocelles (about +40%).
What of you knows a devices that could resolve my problem?  Unfortunately I 
cannot modify the PCB, but I could replace the Altera EPLD with any other 
CPLD.
Thanks
 

Unfortunately, I can't think of many options for you, exccept to modify
the PCB.  The package you picked, 144pin flat pack suppoprts your
device and the smaller one.  There is one more larger device in the
Max3000 family, but it is also in a larger package.

If you try to switch to an alternate device, another brand, etc you
will also be in a position of having to rework the PCB, so if you are
going to have to do that you might as well stay with a device that you
know.

Your other options, may be optimizations or elimimating some of the
logic in the device and moving it into firmware, etc, but trying to
gain 40% on a fairly large device is not going to be an easy task.

Sky wrote:

> In a project I use the Altera EPM3256ATC144-10.
> Now I have the necessity to make some changes to the project, but I don't 
> have enough macrocells in the actual devices.
> Alteras doesn't have a pin-to-pin compatible EPLD  with the EPM3256ATC144-10 
> but with more macrocelles (about +40%).
> What of you knows a devices that could resolve my problem?  Unfortunately I 
> cannot modify the PCB, but I could replace the Altera EPLD with any other 
> CPLD.

Depending on the required speed you may connect wires to the 144 
pads... and connect then to an external box containing whatever.
Yes, I'm aware the wires are very fine. Thus, I'd rather
1) do a new pcb
2) squeeze a reduced functionality in the existing part.

Rene
-- 
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

That sounds like a wonderfull recipe for field failures if carried to
production.  I might say that it would be workable for a prototype, but
I wouldn't go much farther than that.

You indicated in your original post that you are not able to modify the
PCB.  Is there a real reason for this or is it just a case of where MGT
doesn't WANT to modify the PCB?  Quite frankly, often times I have
found that far more enegy is spent attempting to take a short cut
around something and failing than would have been spent to do it right
the first time.

Guys,
This is a long history. The project doesn't only include the EPLD, but also 
many other expensive components.
Unfortunately the change will interest a lot of board already sold.
To change the PCB is certainly possible and I believe that this is the best 
solution, but it is not acceptable for the marketing.
Someone has advised to look at the Lattice or Actel. products. I will look 
for there also.
The solution proposed by Rene would be a true folly, also for a prototype.
Thanks 

Sky wrote:
> Guys,
> This is a long history. The project doesn't only include the EPLD, but also 
> many other expensive components.
> Unfortunately the change will interest a lot of board already sold.
> To change the PCB is certainly possible and I believe that this is the best 
> solution, but it is not acceptable for the marketing.
> Someone has advised to look at the Lattice or Actel. products. I will look 
> for there also.
> The solution proposed by Rene would be a true folly, also for a prototype.

Unfortunately some of the pins have a fixed assignment,
they usually are the programming pins TCLK, TMS, TDI,
TDO and CLK plus the power pins. At least Altera has
no system as to assigning these pins over the families.
Meaning in most cases the footprint is not upgradeable.
And since the manufacturer do not talk to each other
in the interest of the customers, you cannot expect a
competitor product to fit into the footprint what
the fixed pins concerns.

Rene
-- 
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

On Fri, 10 Feb 2006 14:23:39 +0100, "Sky" <dev2-renato_noSpam@usa.net> wrote:
>In a project I use the Altera EPM3256ATC144-10.
>Now I have the necessity to make some changes to the project, but I don't 
>have enough macrocells in the actual devices.
>Alteras doesn't have a pin-to-pin compatible EPLD  with the EPM3256ATC144-10 
>but with more macrocelles (about +40%).
>What of you knows a devices that could resolve my problem?  Unfortunately I 
>cannot modify the PCB, but I could replace the Altera EPLD with any other 
>CPLD.
>Thanks

There are companies that make transition boards (including customs) that
have a footprint on the bottom (and pins) that match an existing board layout
and on the top is a new foot print or even room for multiple chips. This
would allow you to keep existing boards, and change over to prettty much
anything on the top side of the board (CPLD, FPGA, other vendors, ...)

Of course, you need the vertical clearance for this type of desperate
alternative, and maybe horizontal clearance too.

   http://www.arieselec.com/products/correct.htm

plus, they will do custom designs.

Philip


Philip Freidin
Fliptronics

In article <yS5Hf.4488$9G6.474@tornado.fastwebnet.it>, dev2-
renato_noSpam@usa.net says...
> The solution proposed by Rene would be a true folly, also for a prototype.
> Thanks 

How about an adapter PCB?  Put a "bigger" part on the board and 
mount the board in place of the old part.   Kind of like those 
adapter boards that let you adapt an SMT part to a DIP socket or 
other footprints.

Sky wrote:

> Guys,
> This is a long history. The project doesn't only include the EPLD, but also 
> many other expensive components.
> Unfortunately the change will interest a lot of board already sold.
> To change the PCB is certainly possible and I believe that this is the best 
> solution, but it is not acceptable for the marketing.

That's fine, they always ask for that :)

  What you do then, is what Philips suggests, and create a carrier PCB,
that underneath/on edges looks like a TQFP144, and on the top,
has whatever package/device/psu fits.
  Maybe a BGA MachXO, MAX II if the IO voltages will allow.

Then, give them the price for that option.
Nothing like some $$ to sharpen their focus :)

-jg

Sky wrote:
> Guys,
> This is a long history. The project doesn't only include the EPLD, but also
> many other expensive components.
> Unfortunately the change will interest a lot of board already sold.

If you've got product in the field and your modifications don't fit
into the existing device, there's not a whole lot you can do for those
customers, unless you're willing to recall things.

> To change the PCB is certainly possible and I believe that this is the best
> solution, but it is not acceptable for the marketing.

> Someone has advised to look at the Lattice or Actel. products. I will look
> for there also.

Forget about that; the other vendors' parts won't be pin-compatible,
even if they ARE available in the same package.

-a