R-Tile Avalon® Streaming Intel® FPGA IP for PCI Express* User Guide
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6.3. Signal Tap Logic Analyzer
You can use the Signal Tap Logic Analyzer to monitor the top-level signals below from the R-Tile Avalon-ST IP for PCIe as an additional debug tool for PCIe issues.
Signal | Description | Expected Value for Successful Link-up |
---|---|---|
ninit_done | A "1" on this active-low signal indicates that the FPGA device is not yet fully configured. A "0" indicates the device has been configured and is in normal operating mode. You need to instantiate the Reset Release IP and connect the output of that IP to ninit_done. |
1'b0 |
pin_perst_n_o | This output signal to the FPGA fabric indicates if PERST# is asserted. | 1'b1 |
pX_reset_status_n_o | This active-low signal is held low until pin_perst_n has been deasserted and the PCIe Hard IP has come out of reset. This signal is synchronous to coreclkout_hip. Traffic between the user logic in the FPGA core and the IP can start when pX_reset_status_n_o is asserted high. |
1'b1 |
pX_link_up_o | When asserted, this signal indicates the link is up at the Physical Layer. | 1'b1 |
pX_dl_up_o | When asserted, this signal indicates the Data link (DL) Layer is active. | 1'b1 |
pX_ltssm_state_delay_o[5:0] | Indicates the LTSSM state. Note that there is a time difference between the actual link state at the physical level and the time it takes to reflect its value on this signal. | 6'h11 (L0) |