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ETHERNET COMMUNICATION MODULE
Multicast address filtering
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Multicast address filtering
The RX-WR logic contains a programmable 8-entry multicast address filter that
provides more restrictive filtering than that available in the MAC using the SAL. Only
multicast addresses that match those programmed into the filter will be accepted.
Filter entries Each entry in the filter consists of a 48-bit destination address, an enable bit, and a
48-bit mask. The mask contains a 1 in each bit position of the address that is used in
the address filter.; this is used to extend the range of each entry.
Multicast address
filter registers
Multicast address
filtering example
1
To accept only multicast packets with destination address 0x01_00_5E_00_00_00
using entry 0, the registers are set as shown:
RPETFUN MAC1 1 0 MAC TX logic
MIIM MII Management
Configuration register
1 0 MAC MIIM logic
Bit field Register Active
state
Default
state
Modules reset
Register Description
MFILTL [7:0] Lower 32 bits of multicast address
MFILTH [7:0] Upper 16 bits of multicast address
MCMSKL Lower 32 bits of multicast address mask
MCMSKH [7:0] Upper 16 bits of multicast address
MFILTEN Per-entry enable bits
Register Value Function
MFILTEN 0x1 Enable entry 0
MFILTL0 0x5E_00_00_00 Lower 32 bits of multicast address
MFILTH0 0x01_00 Upper 16 bits of multicast address
MCMSKL0 0xFFFF_FFFF Include all of the lower 32 bits of the multicast address
in the comparison.
MCMSKH0 0xFFFF Include all of the upper 16 bits of the multicast address
in the comparison