Fast Ethernet Controller
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 35-27
Data length is the number of octets the Ethernet controller should transmit from this BD data buffer. This
value should be greater than zero. The CP never modifies the data length in a TxBD.
Tx data buffer pointer, which contains the address of the associated data buffer, can be even or odd. The
buffer can reside in external memory. The CP never modifies the buffer pointer.
10–13 RC Retry count. Indicates the number of retries required for this frame to be successfully sent. If RC =
0, the frame is sent correctly the first time. If RC = 15 and RET_LIM = 15 in the parameter RAM, 15
retries were needed. If RC = 15 and RET_LIM > 15, 15 or more retries were needed. The Ethernet
controller updates RC after sending the buffer.
14 UN Underrun. The Ethernet controller encountered a transmitter underrun condition while sending the
associated buffer. The Ethernet controller updates UN after sending the buffer.
15 CSL Carrier sense lost. Carrier sense is lost during frame transmission. The Ethernet controller updates
CSL after sending the buffer.
Table35-11. Ethernet TxBD F ield Definitions (continued)
Field Name Description