User guide

Follow these steps to recalibrate the PMA:
1. Request access to the internal configuration bus by writing 0x2 to offset address 0x0[1:0].
2. Wait for reconfig_waitrequest to be deasserted (logic low).
3. To recalibrate the PMA, write 0x1 to bit[2] or bit[5] of address 0x100 of the PMA.
4. Release the internal configuration bus to PreSICE to perform recalibration by writing 0x3 to offset
address 0x0[1:0]h. Calibration is completed when cal_busy is deasserted (logic low).
5. Request access to the calibration registers by writing 0x2 to offset address 0x0[1:0].
6. Wait for reconfig_waitrequest to be deasserted (logic low).
7. Read address 0x101 to check the calibration status (pass or fail).
8. Release the internal configuration bus to PreSICE by writing 0x3 to offset address 0x0[1:0]. The PMA
calibration is complete at this stage.
Note:
If you do not intend to check calibration status (pass or fail), you can skip steps 5 through 8.
CDR calibration, RX offset cancellation calibration, and TX termination calibration share the same PMA
offset address. If you want to calibrate the CDR, you can enable CDR and offset cancellation calibration
together by setting bit[1] and bit[2] at the same time. CDR calibration is processed first, followed by offset
cancellation calibration.
Related Information
Transceiver Channel Calibration Registers on page 7-3
For more details about PMA recalibration
Recalibration After Transceiver Reference Clock Frequency or Data Rate Change
User recalibration is required if:
• During device power up, CLKUSR is asserted and running, but the transceiver reference clock remains
deasserted until after the power up process is complete.
• During device power up, CLKUSR and the transceiver reference clock are asserted and running. When
the device power up process is complete, the transceiver reference clock changes frequency. Either the
transceiver reference clock could become unstable, or your application requires a different transceiver
referece clock during normal operation, which could cause a data rate change.
• After device power up in normal operation, you reconfigure the transceiver data rate.
7-10
Recalibration After Transceiver Reference Clock Frequency or Data Rate...
UG-01143
2015.05.11
Altera Corporation
Calibration
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