Re: Xilinx FPGA - Wrongly Translated Inputs

Hello everyone,

> >I'm currently using Xilinx ISE 7.1i with the ModelSim XE III/Starter >6.0a simulator. The FPGA which I am downloading my design onto is a >Spartan IIE (it's on the Spartan IIE LC Development Kit, with an >XC2S300E device). > >A word of thanks to all those who have helped me in my previous posts >before; you've all been a big, BIG help, and I really appreciate it. > >I finally found the root of the problem I was having before. The >translated verilog model, when simulated, gives me wrong outputs, as >compared to the behavioural model. After thorough checking of the >simulation results, I realised that all my inputs were wrongly >translated and mapped! > >My mapped inputs were all in a haywire (e.g. clock has become reset, >reset has become cs, sck has become another signal, etc.). Is this the >tool's limitation? There were no errors in my design. Neither were >there any errors in my Translate, Map or PAR reports. I ran an Assign >Package Pins Post-Translate, but I'm not sure if I should make any >changes to the LOC-ed input and outpins which I did earlier in Edit >Constraints (Text). > >Any suggestions as to how I can solve this problem? Please help. > >Thanks very much in advance. > >Regards, >Chloe

yes, there is one important improvement: do assign package-pins pre-translate. In such a way, every pñin will be correctly assigned from the beginning.

Assigning pins post-translate is simply a tool fro some kind of tests, it is not a tool for production.

Regards,

-- Zara

Reply to
Zara
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Zara: Hi, and thanks for your advice. I did assign package-pin pre-translate, and I deduced from the Translate Report that all the I/O pins were assigned and translated properly as there were no errors in the report. Thus I wonder how Assign Package Pins Post-Translate is used, if I have already done a pin assignment before I even synthesised my design.

I just do not understand how my I/O pins could be translated wrongly. Could it be that I mis-configured the ISE?

Thanks.

~Chloe~

Reply to
Chloe

The problem with Postr_translate assignment is that it will be lost if you translate the project again. That is why it is only used for debugging purposes (sending some internal signal to a pin, for instance).

The *used* pins should always be LOCed in the UCF file, so they retain their position from one translation to the next.

Regards,

Zara

Reply to
Zara

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