Programmer’s Guide BCM5722
10/15/07
Broadcom Corporation
Document 5722-PG101-R Transceiver Registers Page 444
AUXILIARY CONTROL REGISTER (PHY_ADDR = 0X1, REG_ADDR = 18H, SHADOW = 000,
NORMAL)
A shadow value of 000 represents normal operation.
Note: To read MII Register 18h, Shadow Register xxx:
1 Write register 18h Shadow Register 111.
Bit 15 = 0.
Bits [14:12] = xxx (Shadow Register value).
Bits [2:0] = 111 (Miscellaneous Control).
2 Read Register 18h.
Data read is the value from Shadow Register xxx.
Bits [2:0] = xxx (Shadow Register value).
To write MII Register 18h, Shadow Register
yyy:
1 Write Register 18h.
Bits [15:3] = data to write.
Bits [2:0] = yyy (Shadow Register value).
Table 508: Auxiliary Control Register (PHY_Addr = 0x1, Reg_Addr = 18h, Shadow = 000, Normal)
Bit Field Description Init Access
15 External Loopback When bit 15 is a 1, external loopback operation is enabled. A
special cable must be inserted to provide a looped signal path.
When the bit is 0, normal operation resumes.
• 1 = External Loopback Enabled.
• 0 = Normal Operation.
0R/W
14 Extended Packet
Length
When bit 14 of the Auxiliary Control Register is written to 1, the
BCM5722 Ethernet controller receives packets up to 25 KB in
length. When the bit is written to 0, the BCM5722 Ethernet
controller only receives packets up to 4.5 KB in length.
• 1 = Allow reception of extended length packets.
• 0 = Allow normal length Ethernet packets only.
0R/W
13:12 Edge Rate Control
(1000BASE-T)
Bits 13 and 12 of the Auxiliary Control Register control the edge
rate of the transmit DAC output waveform.
• 00 = 4 ns.
• 01 = 5 ns.
• 10 = 3 ns.
• 11 = 0 ns.
00 R/W
11 Reserved Write as 0, ignore on read. 0 R/W
10 Transmit mode Bit 10 of the Auxiliary Control Register must always be written to
1 for normal PHY operation.
• 1 = Normal operation.
• 0 = Test mode.
1R/W
9:8 Reserved Write as 0, ignore on read. 0 R/W
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