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ADSP-BF537 Blackfin Processor Hardware Reference
8-13
Ethernet MAC
•
End of frame
– At the end of the frame, the MAC issues a finish
command to the DMA controller, causing it to advance to the next
(status) descriptor.
•
Status
– The MAC then transfers the frame status into the status
buffer. The frame status structure contains the length of the frame
data. The MAC then issues another finish command to complete
the status DMA buffer.
•
Interrupt
– Upon completion, the DMA may issue an interrupt, if
the descriptor was programmed to do so. The DMA then advances
to the next (data) descriptor, if any.
Frame Reception and Filtering
Frame data written to memory normally includes the Ethernet header
(destination MAC address, source MAC address, and length/type field),
the Ethernet payload, and the Frame Check Sequence (FCS) checksum,
but not the preamble. If the
RXDWA
bit in
EMAC_SYSCTL
is 1, then the first
16-bit word is all-zero to pad the frame. The data written includes all
complete bytes for which the received data valid (
ERxDV
) pin on the MII
interface was asserted after but not including the start of frame delimiter
(SFD) nibble (1011).The preamble and any other nibbles prior to the
SFD are also not included.
The MAC applies two filtering mechanisms to received frames: the
address filter and the frame filter. The address filter considers only the
destination MAC address and provides control over the reception of uni-
cast, multicast, and broadcast addresses. The frame filter considers the
entire frame and provides control over reception of frames with errors and
of MAC control frames.
Содержание Blackfin ADSP-BF537
Страница 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...