Hello all,
Forgive me in advance for the long plea for help.
Would anyone be kind enough to troubleshoot my implementation of the EDK 8.1i flow for my production board?
I have implemented a good deal of my project firmware on the Spartan 3 evaluation board with great success. However, upon receipt of my 3E based prototype hardware, I have had nothing but problems successfully porting my design from evalution hardware to prototype hardware.
NOTE: On occasion, the firmware will operate as expected on the prototype board ruling out (hopefully) any board level issues.
My issues seem to be more related to the EDK flow itself or perhaps my lack of understanding of aforementioned EDK flow.
## Physical Differences ## The only differences between the prototype hardware and the evaluation platform wrt the FPGA are as follows:
(1) 500E vs. 200 (2) 100MHz LVDS clock vs. 50 MHz
I have inserted the differential-to-single-ended buffers as per the Xilinx app note regarding differntial clocks.
## The Working Hack ## I can take the previous design targeted for the evaluation board (Spartan 3 Starter) and do the following:
(1) Change the target hardware to the Spartan 3E 500E (2) Insert the differential input buffer (3) Modify the evaluation board UCF to accomadate the prototype implementation
This method works. However, the boad rate (9600bps) is off by a factor of the clock speed multiple (x2).
## The Failed Flow ## Creating a new project targeted towards my prototype hardware (3E@100MHz) fails miserably. Despite repeated efforts across many variations on a theme, I can't even implement a STDIO RS232 interface executing the puked up diagnostic routines. PAR takes a rediculously long period of time and timing constraints seem to complicate the issue.
I'm sure I haven't provided enough pertinent information to characterize my problem. So, if anyone has any ideas or question which would lead me in the correct direction I'd be very appreciative. This exercise seems very straight forward and I'm at a loss as to why I'm having such a hard time doing something so simple.
Thanks :)