Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 7/19/2024
Public

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5.1.7.21. Setting up the Time-Based Scheduling Function

The launch time is programmed in the context transmit descriptors in the DMA configurations and is driven as a control word in MTL configurations as follows:
  • The OSTC and launch time features are mutually exclusive and must not be used together; in case of a conflict (if OSTC = LTV = 1 in MTL configuration), priority is given to OSTC and the launch time is ignored.
  • In DMA configuration, if a context descriptor is received with a valid OSTC, TBSV, and LTV values, the launch time/GSN is ignored.
Note:
  • For a proper TBS usage, the application must update tail pointer only after adding context as well as the first normal descriptor in the transmit ring.
  • Use separate channel (without TBS enabled) for time critical traffic. Mixing such traffic with TBS enabled traffic can cause delays in transmitting time critical traffic.