40.5.1.1 Configuration

Initialization of the EMAC configuration (e.g., loop-back mode, frequency ratios) must be done while the transmit and receive circuits are disabled. See the description of the EMAC_NCR and EMAC_NCFGR earlier in this document.

To change loop-back mode, the following sequence of operations must be followed:

  1. Write to EMAC_NCR to disable transmit and receive circuits.
  2. Write to EMAC_NCR to change loop-back mode.
  3. Write to EMAC_NCR to re-enable transmit or receive circuits.
    Note: These writes to EMAC_NCR cannot be combined in any way.