56.7.1.4 Address Matching

The GMAC Hash register pair and the four Specific Address register pairs must be written with the required values. Each register pair comprises of a bottom register and top register, with the bottom register being written first. The address matching is disabled for a particular register pair after the bottom register has been written and re-enabled when the top register is written. Each register pair may be written at any time, regardless of whether the receive circuits are enabled or disabled.

As an example, to set Specific Address 1 register to recognize destination address 21:43:65:87:A9:CB, the following values are written to Specific Address 1 Bottom register and Specific Address 1 Top register:

Specific Address 1 Bottom register bits 31:0 (0x98): 0x8765_4321.
Specific Address 1 Top register bits 31:0 (0x9C): 0x0000_CBA9.

Note: The address matching is the first level of filtering. If there is a match, the screeners are the next level of filtering for routing the data to the appropriate queue. See Priority Queueing in the DMA for more details.