Motorola MCF5281, MCF5282 user manual 17-25

Models: MCF5282 MCF5281

1 816
Download 816 pages 28.97 Kb
Page 381
Image 381

 

 

Programming Model

 

Table 17-12. EIR Field Descriptions (continued)

 

 

 

 

Bits

Name

Description

 

 

 

 

 

28

GRA

Graceful stop complete. This interrupt will be asserted for one of

 

 

 

three reasons. Graceful stop means that the transmitter is put into

 

 

 

a pause state after completion of the frame currently being

 

 

 

transmitted.

 

 

 

1) A graceful stop, which was initiated by the setting of the

 

 

 

TCR[GTS] bit is now complete.

 

 

 

2) A graceful stop, which was initiated by the setting of the

 

 

 

TCR[TFC_PAUSE] bit is now complete.

 

 

 

3) A graceful stop, which was initiated by the reception of a valid

 

 

 

full duplex flow control “pause” frame is now complete. Refer to

 

 

 

the “Full Duplex Flow Control” section of the Functional

 

 

 

Description chapter.

 

 

 

 

 

27

TXF

Transmit frame interrupt. This bit indicates that a frame has been

 

 

 

transmitted and that the last corresponding buffer descriptor has

 

 

 

been updated.

 

 

 

 

 

26

TXB

Transmit buffer interrupt. This bit indicates that a transmit buffer

 

 

 

descriptor has been updated.

 

 

 

 

 

25

RXF

Receive frame interrupt. This bit indicates that a frame has been

 

 

 

received and that the last corresponding buffer descriptor has been

 

 

 

updated.

 

 

 

 

 

24

RXB

Receive buffer interrupt. This bit indicates that a receive buffer

 

 

 

descriptor has been updated that was not the last in the frame.

 

 

 

 

 

23

MII

MII interrupt. This bit indicates that the MII has completed the data

 

 

 

transfer requested.

 

 

 

 

 

22

EBERR

Ethernet bus error. This bit indicates that a system bus error

 

 

 

occurred when a DMA transaction was underway. When the

 

 

 

EBERR bit is set, ECR[ETHER_EN] will be cleared, halting frame

 

 

 

processing by the FEC. When this occurs software will need to

 

 

 

insure that the FIFO controller and DMA are also soft reset.

 

 

 

 

 

21

LC

Late collison. This bit indicates that a collision occurred beyond the

 

 

 

collision window (slot time) in half duplex mode. The frame is

 

 

 

truncated with a bad CRC and the remainder of the frame is

 

 

 

discarded.

 

 

 

 

 

20

RL

Collision retry limit. This bit indicates that a collision occurred on

 

 

 

each of 16 successive attempts to transmit the frame. The frame is

 

 

 

discarded without being transmitted and transmission of the next

 

 

 

frame will commence. Can only occur in half duplex mode.

 

 

 

 

 

19

UN

Transmit FIFO underrun. This bit indicates that the transmit FIFO

 

 

 

became empty before the complete frame was transmitted. A bad

 

 

 

CRC is appended to the frame fragment and the remainder of the

 

 

 

frame is discarded.

 

 

 

 

 

18–0

Reserved, should be cleared.

 

 

 

 

 

MOTOROLA

Chapter 17. Fast Ethernet Controller (FEC)

17-25

Page 381
Image 381
Motorola MCF5281, MCF5282 user manual 17-25