SPRUII0F May 2019 – June 2024 TMS320F28384D , TMS320F28384D-Q1 , TMS320F28384S , TMS320F28384S-Q1 , TMS320F28386D , TMS320F28386D-Q1 , TMS320F28386S , TMS320F28386S-Q1 , TMS320F28388D , TMS320F28388S
The auxiliary snapshot feature allows you to store a snapshot of the system time based on an external event. This feature is independent of whether the system time is generated internally or given as input (through the Subsystem register).
Two auxiliary snapshot input time stamps can be captured on a single common auxiliary snapshot FIFO. The snapshots taken for any input are stored in a common FIFO. The application can read the MAC_Time- stamp_Status register to know the timestamp of which input is available for reading at the top of this FIFO.
The MAC stores these snapshots in a FIFO of depth 4. Only 64-bits of the timestamp are stored in the FIFO. You can read the upper 16-bits of seconds from the MAC_System_Time_Higher_Word_Seconds register when it is present. When a snapshot is stored, the MAC indicates this to the application with an interrupt. The value of the snapshot is read through a FIFO register access. If the FIFO becomes full and an external trigger to take the snapshot is asserted, a snapshot trigger-missed status (ATSSTM) is set in the MAC_Timestamp_Status register. This indicates that the latest auxiliary snapshot of the timestamp is not stored in the FIFO. The latest snapshot is not written to the FIFO when it is full.
When an application reads the 64-bit timestamp from the FIFO, the space becomes available to store the next snapshot. You can clear a FIFO by setting the ATSFC bit in MAC_Auxiliary_Control register. When multiple snapshots are present in the FIFO, the count is indicated in Bits[27:25] of MAC_Timestamp_Status register.