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Altera_Forum
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17 years ago

Timequest constrains for async SRAM

Any samples about how to constrain an async SRAM interface? Timequest doesn't seem to support the required constrains. For reading, you need the sum of tCO and tSU, and for writing you need dat...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

I finally followed Rysc advice. Forced Fast I/O in the ports. Made a manual computation based on the Datasheet Report. And made some approximate constrains.

The only minor problem with this approach is that you must be careful about the Delay Chain that the fitter might implement. The fitter is doing a great job, and will optimize the Delay Chain automatically for getting the center of the eye according to yout setup/hold max/min constrains. But because the constrains aren't really accurate, the Delay Chain implemented might be actually far from optimal.

Not big deal, just important to remember to use one of the methods to disable the Delay Chain.

Just to make sure I was not making any mistake, I invested making a script to check the actual real slack. Not too difficult using the "get datasheet" command.

Thank you all.