LXT972 Level One, LXT972 Datasheet - Page 16

• Manufacturer Part Number: LXT972
• Description: 3.3V Dual-Speed Fast Ethernet Transceiver Datasheet
• Manufacturer: Level One

LXT972 3.3V Dual-Speed Fast Ethernet Transceiver
Hardware Configuration Settings
The LXT972 provides a hardware option to set the initial
device configuration. The hardware option uses the three
LED driver pins. This provides three control bits, as listed
in
drain or open-source circuits as shown in
Table 8:
16
1. Refer to
Auto-Neg
Table
Disabled
Enabled
.
8. The LED drivers can operate as either open-
Desired Mode
Table 7 on page 9
Hardware Configuration Settings
100 Only
(Mbps)
Speed
10/100
100
10
for LED/CFG pin assignments.
Duplex
Full or
Only
Half
Half
Half
Half
Half
Full
Full
Full
High
High
High High
High High High
Low
Low
Low
Low
1
Pin Settings
LED/CFG n
Figure
High
High High
Low
Low
Low
Low
2
6.
High
High
Low
Low
Low
Low
1
3
AutoNeg
0.12
1
0
Control Register
Figure 6: Hardware Configuration Settings
Speed
LED/CFG Pin
1. The
LED/CFG Pin
0.13
0
1
1
automatically adjust their polarity
upon power-up or reset.
Resulting Register Bit Values
0.8
FD
LED/CFG
0
1
0
1
0
1
0
1
Configuration Bit = 0
Configuration Bit = 1
100FD
4.8
0
1
0
1
Auto-Neg Advertisement
pins
Auto-Negotiation
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100TX
4.7
1
1
1
1
will
N/A
10FD
4.6
0
0
0
1
3.3V
10T
4.5
0
0
1
1