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4.4.3. PTP Client Flow
The figures below depict the TX and RX client flows described in the PTP TX Client Flow and PTP RX Client Flow sections.
- A: Reading TX raw offset data from IP
- B: Calculating the TX offset value
- C: Writing calculated TX offset value to the IP
- D: Reading RS-FEC cw_pos value from the IP
- E: Calculating cw_pos adjustment value
- F: Writing adjustment value to the IP
- G: Reading RX raw offset data from IP
- H: Calculating the RX offset value
- I: Writing calculated RX offset value to the IP
- G: Reading RX raw offset data from IP
- H: Calculating the RX offset value
- I: Writing calculated RX offset value to the IP
Term | Meaning |
---|---|
UI | Unit interval. Indicates bit time of one serial bit for specific speed. Unit interval is defined in 32-bit format, where bit [31:28] represent bit time in nanoseconds (ns) and bit [27:0] represent bit time in fractional nanoseconds (fns). |
PL | Total number of PMA physical lanes of the variant |
VL | Total number of virtual lanes of the variant |
apl | Actual number of specific physical lane in a PMA quad. Possible values are 0, 1, 2, and 3. For more information, refer to the Building Blocks chapter in the F-tile Architecture and PMA and FEC Direct PHY IP User Guide. |
pl | Logical number corresponding to a specific physical lane. pl=0 typically refers to the top-most active physical lane. |
fl | Logical number of a specific FEC lane |
vl | Logical number of a specific virtual lane |
read(reg_name) | Performs CSR read from the reg_name register |
write(reg_name, value) | Performs CSR write with value to the reg_name register. |
tx_pma_delay_ui | Specifies TX serializer latency (in UI) |
rx_pma_delay_ui | Specifies RX deserializer latency (in UI) |
tx_external_phy_delay | Specifies TX external Ethernet PHY latency and board trace delay (in ns) |
rx_external_phy_delay | Specifies RX external Ethernet PHY latency and board trace delay (in ns) |
UI Format
The UI format differs from the format of other variables. UI uses the {4-bit ns, 28-bit fractional ns} format. Other variables defined in the PTP TX/RX client flows use the {N-bit ns, 16-bit fns} format, where N is the largest number to store the calculation's max value.
If you use UI format in your calculation, you must convert the result to a 16-bit fractional nanoseconds (fns) format.