GD32F20x User Manual
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ENET_MAC_FRMF register and setting the corresponding HUF or HMF bit in the
ENET_MAC_FRMF register.
Broadcast frame destination address filter
At default, the MAC unconditionally receives the broadcast frames. But when setting BFRMD
bit in register ENET_MAC_FRMF, MAC discards all received broadcast frames.
Unicast frame source address filter
Enable MAC address 1 to MAC address 3 register and set the corresponding SAF bit in the
MAC address high register, the MAC compares and filter the source address (SA) field in the
received frame with the values programmed in the SA registers. MAC also supports the group
filter on the source address. If the SAFLT bit in frame filter register ENET_MAC_FRMF is set,
MAC drops the frame that failed the source address filtering; meanwhile the filter result will
reflect by SAFF bit in RDES0 of DMA receive descriptor. When the SAFLT bit is set, the
destination address filter is also at work, so the result of the filter is simultaneous determined
by DA and SA filter. This means that, as long as a frame does not pass any one of the filters
(DA filter or SA filter), it will be discarded. Only a frame passing the entire filter can be
forwarded to the application.
Reverse filtering operation
MAC can reverse filter-match result at the final output whether the destination address filtering
or source address filtering. By setting the DAIFLT and SAIFLT bits in ENET_MAC_FRMF
register, this address filter reverse function can be enabled. DAIFLT bit is used for unicast
and multicast frames’ DA filtering result, SAIFLT bit is used for unicast and multicast frames
SA filtering result.
The following two tables summarize the destination address and source address filters
working condition at different configuration.
Table 27-4. Destination address filtering table
Frame
Type
PM
HPFL
T
HUF DAIFLT
HM
F
MFD
BFRM
D
DA filter operation
Broadcast
1
-
-
-
-
-
-
Pass
0
-
-
-
-
-
0
Pass
0
-
-
-
-
-
1
Fail
Unicast
1
-
-
-
-
-
-
Pass all frames
0
-
0
0
-
-
-
Pass on perfect/group filter match
0
-
0
1
-
-
-
Fail on perfect/group filter match
0
0
1
0
-
-
-
Pass on hash filter match
0
0
1
1
-
-
-
Fail on hash filter match
0
1
1
0
-
-
-
Pass on hash or perfect/group filter
match
0
1
1
1
-
-
-
Fail on hash or perfect/group filter match
Multicast
1
-
-
-
-
-
-
Pass all frames
Содержание GD32F20 Series
Страница 1: ...GigaDevice Semiconductor Inc GD32F20x ARM Cortex M3 32 bit MCU User Manual Revision 2 2 Oct 2019 ...
Страница 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Страница 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Страница 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
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Страница 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...