Chapter 12: 10/100 IEEE802.3 Media Access Controller
TX7901 User’s Manual (Rev. 6.30T – Nov, 2001)
12-13
Bit(s)
Field
R/W
Description
is reset, the MAC will not self-initiate any flow control algorithms.
7
RxNoCRC
R/W
Strip CRC (0)
When set, the MAC strips the CRC (the last 4 bytes) from all frames being received.
6
RxErr
R/W
Reject Frame MII Receive Error (0)
See note below.
Event counters are updated regardless of the state of this bit.
5
RxFAE
R/W
Reject Frame Alignment Errors (0)
See note.
Event counters are updated regardless of the state of this bit.
4
RxCRCErr
R/W
Reject CRC Error Frames (0)
See note.
Event counters are updated regardless of the state of this bit.
3
RxUND
R/W
Reject Undersized Frames (0)
See note.
Event counters are updated regardless of the state of this bit.
2
RxFRAG
R/W
Reject Fragments (0)
See note.
Event counters are updated regardless of the state of this bit.
1
RxStart
R/W
Receive Start (0)
This bit works with RxEnable. If the RxEnable is “0,” RxStart is ignored. When set, the
MAC enters a running reception state. It will poll the Descriptor first, then transfer the
incoming frame data to memory. When cleared, this bit will stop reception. If this bit is
cleared during the reception of a frame, the frame is completely received before the port
is stopped.
This bit is self-clearing when the reception is stopped (error occurred). To resume the
transmission process, the driver should set this bit again. If the reception is suspended
(Descriptor is not available), it will resume automatically when a new frame arrives.
0
RxEnable
R/W
Receive Port Enable (0)
The reception event counters continue to update, regardless of the state of this bit.
Note
:
If the Reject bits (RFCReg[6:2]) are set, the MAC discards the frame if the RxSOFTh threshold has not
been met. If the RxSOFTh threshold has been met, the MAC sends the frame to memory, and updates the Rx
status.
Table 12-10 Receive Modes when RxAll is 1 or 0
RxAll
RxMulAll
RxIF
RxHP[1]
RxHP[0]
Filtering Mode
1
x
x
x
x
Promiscuous Mode
0
1
x
x
x
Pass all Multicast
0
0
0
0
0
16 perfect filtering
0
0
1
0
0
Inverse filtering
0
0
0
0
1
512-bit hash for multicast, and
one perfect filtering for physical
0
0
0
1
x
512-bit hash only
Содержание TMPR7901
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Страница 14: ...Handling Precautions ...
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