SLAU723A October 2017 – October 2018 MSP432E401Y , MSP432E411Y
Enhanced Descriptors can contain up to eight words (32 bytes) and buffers of up to 8KB (useful for Jumbo frames). Enhanced Descriptors support IEEE 1588-2008 Advanced Timestamp and IPC Full Checksum (Type 2) Offload. These enhanced features are enabled with the TSEN bit of the EMACTIMSTCTRL register and the IPC bit of the EMACCFG register, respectively.
When using Enhanced Descriptors, set the descriptor size to eight words with the Alternate Descriptor Size (ATDS) bit in the Ethernet MAC DMA Bus Mode (EMACDMABUSMOD) register. If these enhanced features are not enabled, the extended descriptors (DES4 to DES7) are not required. Therefore, the software can use Alternate Descriptors with a default size of 16 bytes (4 words). For alternate descriptors, the software should clear the Alternate Descriptor Size (ATDS) bit in the Ethernet MAC DMA Bus Mode (EMACDMABUSMOD) register.
See Section 15.3.3.5.1 and Section 15.3.3.5.2 for more details on the descriptor structure.