EPM3128ATC100-10n is too small

[Altera_Forum]

Hi, 

I am looking to replace the EPM3128ATC100-10n altera part with a device that is at least 10 times bigger than this device. I need at least 600 macro cells for my design. I was looking into the the Cyclone III family it seems to fit my design easily with a lot of room for future expansion. However, I have two questions: 1). Would you recommend another CPLD to meet my needs (above)? I know it is cheaper. 2). Is the Cyclone III more specifically the EP3c25Q240C8N part available now and will be available for a long time?  Sincerely Carpevitam

[Altera_Forum]

I tend to design more in FPGA vs CPLD land, so I can't really give you a good recommendation for you there, other than to look closely to the Max V family (Up to 1700 macrocells or 2210 LE's) 

 The EP3C25 is in full production. And is currently available at Digikey. (Although that package is a non-stock at Arrow) The U256 is probably a much more popular package.. This may be overkill for your design however.  Right now it looks like you are in a 128 macrocells which is approximately equivalent to 208 LE's.  The EP3C25 is 25000 LE's or approximately 15000 macrocells.   The EP3C5 is 5136 LE's or approximately 3160 macrocells,   As far as longevity, they are still in production with Cyclone and Cyclone II devices, so I don't think that's an issue yet. My only concern would be to the package, since the BGA's seem to be more popular these days.  My suggestion is to get your logic design done if possible, then fit it to either Max 5 or Cyclone 3 families.  If you want to go Cyclone III, build the board so it's compatible with all family members in the package.. (Be careful here, some IO's in one device are VCC's/GND's and/or NC in other family members).  That way you can put the biggest family member on the board for the development, then shrink it down for production without changing the board.  Pete

[Altera_Forum]

Using FPGAs instead of a CPLD is also a bit more complicated, it usually requires more different power supplies, and an external flash chip to store the configuration.

[Altera_Forum]

Thank you for your reply. However, I may be ok with the epm3128atc144 device. I changed my if-else statements to case statements, and replace 

some of my logic with a state machine, and now I can fit my design at 32% consumption. I am happy about this, but I would like to understand more about how this happened.

[Altera_Forum]

Hard to say without looking at the code. :) 

Sometimes, minor differences may have impact. One thing to look out if that "if-else" defines priority, while "case" doesn't. Other thing to look out are "don't care" cases.  Taking a look at the RTL also helps sometimes.