SPRUII0F May 2019 – June 2024 TMS320F28384D , TMS320F28384D-Q1 , TMS320F28384S , TMS320F28384S-Q1 , TMS320F28386D , TMS320F28386D-Q1 , TMS320F28386S , TMS320F28386S-Q1 , TMS320F28388D , TMS320F28388S
The registers accessible from the CPU are in the system clock domain and are synchronized to the PDI clock before being used within the EtherCAT IP. Given the frequency ratios and different styles of synchronization schemes, the application needs to assume there is a delay in getting the values transferred from one domain to other. Such a delay can vary based on the frequency of system clock and type of synchronizer used in the path.
For example, a system clock of 200MHz and ESCSS running at 100MHz requires at least 10 clock-system clock cycles delay before values are affected on the other side. If a write occurs to the PDI and some other action is performed elsewhere (not involving the PDI), then the software must perform a simple read to make sure that the write is complete.