SCC Ethernet Mode
MPC885 PowerQUICC Family Reference Manual, Rev. 2
27-12
Freescale Semiconductor
Figure 27-4. Ethernet Address Recognition Flowchart
In group address recognition, the controller determines whether the group address is a broadcast address.
If broadcast addresses are enabled, the frame is accepted, but if the group address is not a broadcast
address, address recognition can be performed on multiple group addresses using the GADDRn hash table.
In promiscuous mode, the controller receives all incoming frames regardless of their address.
27.11 Hash Table Algorithm
Individual and group hash filtering operate using certain processes. The ethernet controller maps any
48-bit address into one of 64 bins, each represented by a bit stored in GADDRx or IADDRx. When a
SET
GROUP
ADDRESS
command is executed, the ethernet controller maps the selected 48-bit address into one
of the 64 bits by passing the 48-bit address through the on-chip 32-bit CRC generator and selecting 6 bits
Check Address
I/G Address
?
Hash_Search
False
G
True
True
Multiple IND
?
Broadcast
Address
Use Indicated
Table
Hash Search
Use Group
Table
Match
?
Match
?
Receive Frame
Ignore REJECT
Receive Frame
Ignore REJECT
Match
?
Receive Frame
Ignore REJECT
PROMISC
?
Start Receive
Discard Frame if REJECT
Discard Frame
is Asserted
I
True
True
False
False
True
True
False
False
?
Broadcast
Enabled
?
True
False
False
Multiple Individual
Addresses
Single
Address
Summary of Contents for PowerQUICC MPC870
Page 98: ...MPC885 PowerQUICC Family Reference Manual Rev 2 I 4 Freescale Semiconductor ...
Page 118: ...MPC885 Overview MPC885 PowerQUICC Family Reference Manual Rev 2 1 20 Freescale Semiconductor ...
Page 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
Page 288: ...MPC885 PowerQUICC Family Reference Manual Rev 2 III 4 Freescale Semiconductor ...
Page 554: ...MPC885 PowerQUICC Family Reference Manual Rev 2 V 6 Freescale Semiconductor ...
Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
Page 1336: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 16 Freescale Semiconductor ...
Page 1358: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 38 Freescale Semiconductor ...
Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Page 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...