LXT972 Level One, LXT972 Datasheet - Page 63

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

Table 50: LED Configuration Register (Address 20, Hex 14)
20.7:4
20.3:2
20.1
20.0
1. R/W = Read /Write
2. Link status is the primary LED driver. The LED is asserted (solid ON) when the link is up.
3. Combined event LED settings are not affected by Pulse Stretch bit 20.1. These display settings are stretched regardless of the value of 20.1.
4. Duplex status is the primary LED driver. The LED is asserted (solid ON) when the link is full duplex.
5. Values are relative approximations. Not guaranteed or production tested.
Bit
RO = Read Only
LH = Latching High
The secondary LED driver (Receive or Activity) causes the LED to change state (blink).
Collision status is the secondary LED driver. The LED changes state (blinks) when a collision occurs.
LED3
Programming
bits
LEDFREQ
PULSE-
STRETCH
Reserved
Name
5
0000 = Display Speed Status
0001 = Display Transmit Status
0010 = Display Receive Status (Default)
0011 = Display Collision Status
0100 = Display Link Status
0101 = Display Duplex Status
0110 = Unused
0111 = Display Receive or Transmit Activity
1000 = Test mode- turn LED on
1001 = Test mode- turn LED off
1010 = Test mode- blink LED fast
1011 = Test mode- blink LED slow
1100 = Display Link and Receive Status combined
1101 = Display Link and Activity Status combined
1110 = Display Duplex and Collision Status combined
1111 = Unused
00 = Stretch LED events to 30 ms.
01 = Stretch LED events to 60 ms.
10 = Stretch LED events to 100 ms.
11 = Reserved.
0 = Disable pulse stretching of all LEDs.
1 = Enable pulse stretching of all LEDs.
Ignore.
Description
– continued
2
2
(Stretched)
(Stretched)
4
LXT972 Register Definitions
(Stretched)
3
3
3
Type
R/W
R/W
R/W
R/W
1
Default
0010
N/A
00
1
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