MPC8280 datasheet(1262/1386 Pages) FREESCALE

1262 / 1386 page

Fast Ethernet Controller

MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

36-28

Freescale Semiconductor

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.

Retransmission limit. The transmitter failed (RET_LIM + 1) attempts to successfully send a message

due to repeated collisions. The Ethernet controller updates RL after sending the buffer.

10–13

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.

Underrun. The Ethernet controller encountered a transmitter underrun condition while sending the

associated buffer. The Ethernet controller updates UN after sending the buffer.

CSL

Carrier sense lost. Carrier sense is lost during frame transmission. The Ethernet controller updates

CSL after sending the buffer.

Table 36-11. Ethernet TxBD Field Definitions (continued)

Field

Name

Description

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