Samsung S3C2501X User Manual page 315

ETHERNET CONTROLLER
7.4.2.3 CAM Control Register
The three acceptance bits (MStation, MGroup, and MBroad) in the CAM control register are used to override the
address comparison mode by the compare enable bit(MCompEn). By setting the CAM control register, it is
possible to accept frames with all types of destination addresses. The three types of destination address are as
follows:
— Broadcast address: defined as FF-FF-FF-FF-FF-FF.
— Unicast (Station) address: addresses with an even first byte. For example, 00-FF-FF-FF-FF-FF.
— Multicast (Group) address: addresses with an odd first byte, but not the Broadcast address. For example, 01-
00-00-00-00-00.
CAM comparison mode: MCompEn = '1', MNegCAM = '0'
The CAM controller compares the destination address of the incoming frame with the CAM addresses enabled by
the CAM Enable (CAMEN) register. The controller accepts only the frames with the matched destination
addresses.
Negative CAM comparison mode: MCompEn = '1', MNegCAM = '1'
The address comparison is same as the CAM comparison mode. But, the CAM controller rejects the frames with
the matched destination addresses and accepts frames with the address outside the CAM address enabled.
No CAM comparison mode: MCompEn = '0'
The CAM controller accepts frames with all types of destination addresses.
Registers Address
CAMCONA 0xF00B0004
CAMCONB 0xF00D0004
Bit Number
[0] Station accept (MStation)
[1] Group accept (MGroup)
[2] Broadcast accept (MBroad)
[3] Negative CAM (MNegCAM)
[4] Compare enable (MCompEn)
[31:5] Reserved
7-26
Table 7-17. CAMCON Register
R/W
R/W
R/W
Bit Name
Set this bit to accept unicast (i.e. station) frames.
Set this bit to accept multicast (i.e. group) frames.
Set this bit to accept broadcast frames.
Set this bit to enable the Negative CAM comparison mode.
Set this bit to enable the CAM comparison mode.
Not applicable.
Description
CAM control
CAM control
Description
S3C2501X
Reset Value
0x00000000
0x00000000