Datasheet
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PREAMBLE | SOF | DEST. ADDR. | SOURCE ADDR. |
(7 BYTES) | (1 BYTE) | (6 BYTES) | (6 BYTES) |
Ethernet frame (1518 BYTES)
TYPE | DATA | FCS | |
(2 BYTES) | (46 - 1500 BYTES) | (4 BYTES) | |
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Ethernet frame with VLAN TAG
(1522 BYTES)
PREAMBLE | SOF | DEST. ADDR. | SOURCE ADDR. | TPID | TYPE | TYPE | DATA | FCS |
(7 BYTES) | (1 BYTE) | (6 BYTES) | (6 BYTES) | (2 BYTES) | (2 BYTES) | (2 BYTES) | (46 - 1500 BYTES) | (4 BYTES) |
Tag Control Information
(TCI)
TPID | USER PRIORITY | CFI | VLAN ID |
(2 BYTES) | (3 BITS) | (1 BIT) | (12 BITS) |
VID: 12 bits defining the VLAN to which the frame belongs
Canonical Address Format Indicator
Indicates frame's priority
Tag Protocol D:
The Ethernet address fields of an Ethernet packet, consists of two
The address check logic filters the frame based on the Ethernet receive filter mode that has been enabled. Filter modes are specified based on the state of the control bits in Table 3.13, "Address Filtering Modes", which shows the various filtering modes used by the MAC. These bits are defined in more detail in Section 4.4.1, "MAC Control Register (MAC_CR)," on page 119.
If the frame fails the filter, the MAC does not receive the packet. The Host has the option of accepting or ignoring the packet.
Table 3.13 Address Filtering Modes| MCPAS | PRMS | INVFILT | HFILT | HPFILT | DESCRIPTION |
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0 | 0 | 0 | 0 | 0 | MAC address perfect filtering only |
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| for all addresses. |
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0 | 0 | 0 | 0 | 1 | MAC address perfect filtering for |
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| physical address and hash filtering |
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| for multicast addresses |
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0 | 0 | 0 | 1 | 1 | Hash Filtering for physical and |
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| multicast addresses |
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0 | 0 | 1 | 0 | 0 | Inverse Filtering |
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X | 1 | 0 | X | X | Promiscuous |
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SMSC LAN9420/LAN9420i | 55 | Revision 1.22 |
| DATASHEET |
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