Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs
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5.1.7.16.1. Initialization Guidelines for System Time Generation
You can enable the timestamp feature by setting Bit 0 of the MAC_Timestamp_Control register. However, it is essential that the timestamp counter must be initialized after this bit is set. Complete the following steps during EMAC initialization:
- Mask the timestamp trigger interrupt by clearing the bit 12 of MAC_Interrupt_Enable register.
- Set bit 0 of MAC_Timestamp_Control register to enable timestamping.
- Program MAC_Sub_Second_Increment register based on the PTP clock frequency.
- You can use either the Coarse Correction Method or the Fine-Correction Method to update the time.
- Program MAC_System_Time_Seconds_Update register and MAC_System_Time_Nanoseconds_Update register with the appropriate time value.
- Set bit 2 in MAC_Timestamp_Control register. The timestamp counter starts operation as soon as it is initialized with the value written in the timestamp update registers. If one-step timestamping is enabled:
- To enable one-step timestamping, program bit 27 of the TDES3 context descriptor.
- Program the registers MAC_Timestamp_Ingress_Asym_Corr and MAC_Timestamp_Egress_Asym_Corr to update the correction field in PDelay_Req PTP messages.
- Enable the MAC receiver and transmitter for proper timestamping.