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Altera_Forum
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11 years ago

Pin Planner LVDS Differential Pair Selection

I am fighting Pin Planner at every turn. In my QSF file, I have the following: set_location_assignment PIN_T22 -to "HSMC_RX_D_N(n)" set_instance_assignment -name IO_STANDARD LVDS -to "HSMC_RX_D...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
11 years ago

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How do I make Pin Planner stop being so mean to me?

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You cannot. Its sole purpose in life is to frustrate you :)

For LVDS signals, you only need to assign the pin and IO_STANDARD to the positive side of the pair, and Quartus will infer the negative pin assignment. This means your top-level entity does not need to include your two signals, i.e., HSMC_RX_D_P and HSMC_RX_D_N, you can just call it HSMC_RX_D and make it LVDS. You then do not need an iobuf at the top-level of your design.

There are other solutions, but this one results in the least code :)

Cheers,

Dave