R-tile Avalon® Streaming Intel® FPGA IP for PCI Express* User Guide

ID 683501
Date 10/06/2021

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4.4.2. Precision Time Measurement (PTM) Interface

Following are the PTM interface signals between the IP and the FPGA core fabric. Only x16 and x8 PCIe modes are supported. The accuracy supported by this interface is +/-50 ns.

Table 24.  PTM Interface Signals
Signal Name Direction Description EP/RP/BP Clock
pX_ptm_context_valid_o Output When this signal is asserted, it indicates that the value present on the ptm_time bus is valid. Hardware will deassert this bit whenever a PTM dialogue is requested and an update is in progress. EP/RP/BP coreclkout_hip
pX_clk_updated_o Output This one clock pulse is an indication that the PTM dialogue has completed and the results of that operation have been driven on the ptm_time bus. EP/RP/BP coreclkout_hip
pX_ptm_local_clock_o[63:0] Output This bus contains the calculated master time at t1’ as indicated in the PCIe spec plus any latency to do the calculation and to drive the value to the requester. EP/RP/BP coreclkout_hip
pX_ptm_manual_update_i Input Asserted high for one coreclkout_hip clock when the user application wants to request a PTM handshake to get a snapshot of the latest time. EP/RP/BP coreclkout_hip

For more details, refer to Section 6.22 Precision Time Measurement (PTM) Mechanism of the PCI Express* Base Specification Revision 5.0 Version 1.0.