Motorola MPC8260 - Manual (Page 902)

30-28 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part IV. Communications Processor Module
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 modiÞes 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 internal or external memory. The CP never modiÞes the
buffer pointer.
10Ð13 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 Þrst 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.
Table 30-11. Ethernet TxBD Field Definitions (Continued)
Field Name Description