AR# 43482: 7 Series Transceivers - Reset Requirements Upon Configuration
7 Series Transceivers - Reset Requirements Upon Configuration
In the 7 series FPGAs GTX/GTH/GTP Transceivers, GTTXRESET and GTRXRESET need to default to Low upon configuration, and to be set to High some time after the configuration is done.
Upon configuration, you must initiate the GTTXRESET and GTRXRESET in sequential mode; that is, RESETOVRD=1'b0 and GTRESETSEL=1'b0.
If RESETOVRD and GTRESETSEL are already defaulted to the above values, then the GT resets: GTTXRESET and GTRXRESET cannot be asserted until a minimum of 500 ns after the configuration is complete. To keep the timing aligned with Figure 2-12 in the 7 Series FPGAs GTS Transceivers User Guide, it might be best to delay the CPLLRESET and the QPLLRESET as well.
If RESETOVRD and GTXRESETSEL are NOT defaulted to the above values, then you must do the following: