lxt975 Intel Corporation, lxt975 Datasheet - Page 17

• Manufacturer Part Number: lxt975
• Description: Fast Ethernet 10/100 Quad Transceivers
• Manufacturer: Intel Corporation

Datasheet
1. Type Column Coding: I = Input, O = Output, A = Analog.
2. The LXT974/975 supports the 802.3 MDIO register set. Specific bits in the registers are referenced using an “X.Y” notation,
1. Type Column Coding: I = Input, O = Output, OD = Open Drain.
2. Unused pins should be tied Low.
3. The LXT974/975 supports the 802.3 MDIO register set. Specific bits in the registers are referenced using an “X.Y” notation,
Pin#
101, 112, 159
41, 119, 120
12
13
10
17
15
16
11
where X is the register number (0-6 or 16-20) and Y is the bit number (0-15).
8
4
1
9
5
2
6
3
where X is the register number (0-6 or 16-20) and Y is the bit number (0-15).
Table 9. LXT974 and LXT975 Miscellaneous Signal Descriptions
Table 10. LXT974 and LXT975 LED Indicator Signal Descriptions
Pin#
2
140
118
109
102
20
19
18
LED0_0
LED1_0
LED2_0
LED3_0
LED0_1
LED1_1
LED2_1
LED3_1
LED0_2
LED1_2
LED2_2
LED3_2
LEDENA
LEDCLK
LEDDAT
Symbol
ADD4
ADD3
ADD2
TEST
RBIAS
CLK25M
RESET
PWRDN
N/C
Symbol
Type
OD
OD
OD
O
O
O
1
LED0 - Ports 0 - 3. In default mode, active Low output indicates transmitter active. However,
LED0 is programmable and may also be set to indicate receiver active, link status or duplex
status. Refer to LED Configuration Register,
programming options.
LED1 - Ports 0 - 3. In default mode, active Low output indicates receiver active. However,
LED1 is programmable and may also be set to indicate link status, duplex status, or operating
speed. Refer to LED Configuration Register,
programming options.
LED2 - Ports 0 - 3. In default mode, active Low output indicates link up. However, LED2 is
programmable and may also be set to indicate duplex status, operating speed or collision.
Refer to LED Configuration Register,
programming options.
LED Enable. Active High output signals external device that LEDDAT is active.
LED Clock. 25 MHz clock for LED serial data output.
LED Data. Serial data output for 24 LEDs (6 x 4 ports) data.
Type
I
I
I
I
I
I
I
I
-
1
Address <4:2>. Set upper three bits of PHY
address. ADD<1:0> are set internally to match
port number as shown at right.
Test. Must be tied Low.
Bias. This pin provides bias current for the internal circuitry. Must be tied to
ground through a 22 k
Clock Input. A 25 MHz clock input is required at this pin. Refer to Functional
Description for detailed clock requirements.
Reset. This active Low input is OR’ed with the control register Reset bit (0.15).
The LXT974/975 reset cycle is extended 205 µ s (nominal) after Reset is de-
asserted.
Power Down. When High, forces LXT974/975 into power down mode. This pin is
OR’ed with the Power Down bit (0.11). Refer to
information.
No Connection. Leave open.
Fast Ethernet 10/100 Quad Transceivers — LXT974/LXT975
Ω
Signal Description
resistor.
Table 51 on page
Signal Description
Table 51 on page
Table 51 on page
68, for details on
3
Table 44 on page 64
2
ADD1
68, for details on
68, for details on
0
0
1
1
ADD0
0
1
0
1
for more
Port
0
1
2
3
17