40.5.1.6 Transmitting Frames

To set up a frame for transmission:

1. Enable transmit in the EMAC_NCR.
2. Allocate an area of system memory for transmit data. This does not have to be contiguous, varying byte lengths can be used as long as they conclude on byte borders.
3. Set-up the transmit buffer list.
4. Set the EMAC_NCR to enable transmission and enable interrupts.
5. Write data for transmission into these buffers.
6. Write the address to transmit buffer descriptor queue pointer.
7. Write control and length to word one of the transmit buffer descriptor entry.
8. Write to the ‘Start Transmission’ bit in the EMAC_NCR.