ADSP-BF537 Blackfin Processor Hardware Reference
8-29
Ethernet MAC
If the
LCRTE
bit is clear and a late collision is detected, the MAC issues a
finish command to the TX DMA controller, advancing the DMA channel
to the status descriptor. The MAC then transfers the TX frame status to
memory and advances to the next frame descriptor for data.
TX Frame Status Classification
The TX frame status buffer and the TX current frame status register pro-
vide a convenient classification of each received frame, representing the
IEEE-802.3 “transmit status” code. The bit layout in the TX frame status
buffer is identical to that in the TX current frame status register, and is
arranged so that exactly one status bit is asserted for each of the possible
transmit status codes defined in IEEE-802.3 section 4.3.2.
The priority order for determination of the transmit status code is shown
in
Table 8-6. TX Transmit Status Priority
Priority
Bit
Bit Name
IEEE transmit
status
Condition
1
4
DMA
underrun
Undefined
The frame was not completely delivered
by DMA
2
2
Excessive
collision
Excessive
collision error
The frame was aborted because of too
many (16) collisions, or because of exces-
sive deferral
3
3
Late
collision
error
Late collision
error status
The frame was aborted because of a late
collision
4
14, 13
Loss of
carrier, no
carrier
Carrier sense was deasserted during some
or all of the frame transmission
(half-duplex only).
5
1
Transmit
OK
Transmit OK
The frame had none of the above condi-
tions
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...