1. Home
  2. Field-Programmable Gate Arrays
  3. FPGA Selection--

FPGA Selection--

I've attempting to select an FPGA for a new design.

The design will have 9 of the following: 12 bit latches 12 bit down counter 1 bit output latch

So one measure of the size might be 25 registers * 9 = 225 registers.

The counting freq is 15 MHz.

The latches get loaded from an existing micro. So I need a 12 input pins for a data buss, 4 input pins for which register, a clock pin and let's say 4 pins for control lines. Along with the 9 output signals.

So another measure is 12+4+1+4+9 = 30 pins not counting power and ground.

It would also be desirable to be packaged in a PLCC but TQFP in ok.

And the device should be reprogrammable using JTAG (add 4 more pins).

Voltage is not much of an issue. However 5 V tolerant I/O would be nice.

I've looked at Lattice and Altera and haven't found the perfect solution. I can use larger than necessary Altera devices (ACEX1K) but that seems to be the wrong direction.

Any suggestions/recommendations.

Thanks George

Reply to
George
Loading thread data ...

PLCC / 5V /15MHz / 225 registers is more trailing edge, so look at Atmel's AT40K FPGA family (meets all features), or possibly a CPLD - Lattices 4000 family have 5V tolerant I/O ?

-jg

Reply to
Jim Granville

There is the XCR3256XL

formatting link

This is a 256 macrocell part that operates at 3.3V. It has the required 225 flops (31 to spare), JTAG and is 5V tolerant on the I/Os. It is offered in both TQ and PLCC packages.

15 MHz would bea "piece of cake". It's overkill in the I/O , but more is better than less. Of course, there is a 1.8V version, but it does note tolerate 5V without extra circuitry on the outside.

Peter Alfke, Xilinx Applications ==================================

Reply to
Peter Alfke

Jim,

Lattice's ispMACH4000 is a great family and available in different packages. However, George mentioned he want's to use a PQFP,and the ispMACH4000 is not available in PQFP. Ttherefore I would like to suggest a M4A3-256/128-10YC. This is the previous generation. If price matters, and George can live with TQPF (which is actual a smaller package) then he can chose the LC4256V-75T100C. This device has 64 IOs.

Regards,

Luc

Reply to
Luc

"George" skrev i meddelandet news: snipped-for-privacy@posting.google.com...

Check out the AT94K10 or AT94K05. This gives you both the (AVR) micro and the FPGA.

--
Best Regards
Ulf at atmel dot com
These comments are intended to be my own opinion and they
may, or may not be shared by my employer, Atmel Sweden.

>
> Thanks
> George
Reply to
Ulf Samuelsson

You don't need an FPGA for something that simple, look at CPLDs.

Reply to
General Schvantzkoph

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.