15.3.11.5 Power-Down and Wake-Up Sequence
The recommended power-down and wake-up sequence is as follows:
- Disable the Transmit DMA (if applicable) and wait for any previous frame transmissions to complete. These transmissions can be detected when TI is set in the Ethernet MAC DMA Interrupt Status (EMACDMARIS) register.
- Disable the MAC transmit and receive state machine by clearing the TE and RE bits in the Ethernet MAC Configuration (EMACCFG) register.
- Wait until the RX DMA empties all the frames from the Rx FIFO to system memory by polling the RXF field of the Ethernet MAC Status (EMACSTATUS) register.
- Enable a power management mode by setting the magic packet, global unicast or remote wake-up enable bit in the EMACPMTCTLSTAT register.
- Enable the MAC receive state machine in the EMACCFG register and enter the Power-Down mode by setting the PWRDWN bit in the EMACPMTCTLSTAT register.
- On receiving a valid remote wake-up frame, the PMT interrupt is set in the EMACRIS register and the Ethernet MAC exits the Power-Down mode.
- Read the EMACPMTCTLSTAT register to clear the PMT interrupt, then enable the other modules in the system and resume normal operation.