TTL Compatible IO from a FPGA

[davidgrm]

interfacing cyclone iii devices with 5v ttl

Hi
I am starting a new design that requires a FPGA that can interface to 74hcxxx logic and also to microcontrollers such as the 80c51. I have being looking at using the Cyclone from Altera but see that it does not really support 5V IO. If you have used this or a similar device for 5v IO I would appreciate your comments

Thanks

David

 

[benradu]

Spartan 2/2E from Xilinx is 5V tolerant.

 

[coolsniper]

now most the fpga work with lvttl (3.3V), but xilinx and altera both provide application notes describling how to design the 5V interface circuits.

 

[davidgrm]

I have not found anything on the Altera or Xilinx sites, and it appears that the older parts that handle 5V are no longer for sale by them

 

[ilikebbs]

why do not you use 3.3v peripheral device??

 

[praveen10]

hi,
u can use APEX family(FPGA) from @ltera that has 5V input tolerant.
Or if u like to have additional chip named level translator it can convert 3.3V to 5 V and vise versa.this would be useful to make ur application very easier.