Owner's manual

Table Of Contents
9-54 DS785UM1
Copyright 2007 Cirrus Logic
1/10/100 Mbps Ethernet LAN Controller
EP93xx User’s Guide
9
9
9
HashTbl
Address:
0x8001_0050 through 0x8001_0057 - 8 Bytes - Read/Write,
when AFP = 111b
Chip Reset:
0x0000_0000
Soft Reset:
Unchanged
Definition:
Hash Table Register. The hash table is used as a way of filtering groups of
addresses in the receiver. Following the reception of the destination address
(first 6 bytes of a receive frame), the upper 6 bits of the computed CRC are
used as an address into the hash table. If the bit accessed by this address is a
“1”, the frame passes the hash table test, if the bit is a “0”, the frame fails the
hash table test.
The hash table may be used for either or both of individual addressed frames
and group address frames, depending on the IAHA and MA bits in RXCtl. A
frame has a group address if the first bit of the frame is a one.
If an individual address frame passes the hash test and the IAHA bit is set, the
frame passes the destination filter.
If a group address frame passes the hash test and the MA bit set, the frame
passes the destination filter.
Bit Descriptions:
HTb: Hash Table entries.
63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48
HTb
47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32
HTb
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
HTb
1514131211109876543210
HTb