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EMAC Module Registers
5.44 MAC Address High Bytes Register (MACADDRHI)
The MAC address high bytes register (MACADDRHI) is shown in
Figure 82
and described in
Table 81
.
Figure 82. MAC Address High Bytes Register (MACADDRHI)
31
24
23
16
MACADDR2
MACADDR3
R/W-x
R/W-x
15
8
7
0
MACADDR4
MACADDR5
R/W-x
R/W-x
LEGEND: R/W = Read/Write; -x = value is indeterminate after reset
Table 81. MAC Address High Bytes Register (MACADDRHI) Field Descriptions
Bit
Field
Value
Description
31-24
MACADDR2
0-FFh
MAC source address bits 23-16 (byte 2)
23-16
MACADDR3
0-FFh
MAC source address bits 31-24 (byte 3)
15-8
MACADDR4
0-FFh
MAC source address bits 39-32 (byte 4)
7-0
MACADDR5
0-FFh
MAC source address bits 47-40 (byte 5). Bit 40 is the group bit. It is forced to 0 and read as 0.
Therefore, only unicast addresses are represented in the address table.
5.45 MAC Index Register (MACINDEX)
The MAC index register (MACINDEX) is shown in
Figure 83
and described in
Table 82
.
Figure 83. MAC Index Register (MACINDEX)
31
16
Reserved
R-0
15
3
2
0
Reserved
MACINDEX
R-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 82. MAC Index Register (MACINDEX) Field Descriptions
Bit
Field
Value
Description
31-3
Reserved
0
Reserved
2-0
MACINDEX
0-7h
MAC address index. All eight addresses share the upper 40 bits. Only the lower byte is unique for each
address. An address is written by first writing the address number (channel) into the MACINDEX
register. The upper 32 bits of the address are then written to the MACADDRHI register, which is
followed by writing the lower 16 bits of the address to the MACADDRLO register. Since all eight
addresses share the upper 40 bits of the address, the MACADDRHI register only needs to be written
the first time.
121
SPRUFL5B – April 2011
EMAC/MDIO Module
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