RTL8305SC Datasheet, PDF (142/160 Pages) List of Unclassifed Manufacturers – SINGLE-CHIP 5-PORT 10/100MBPS SWITCH CONTROLLER WITH DUAL MII INTERFACES

RTL8305SC
Datasheet
port 4 can be tri-stated (disable LED functions) for MII port application by setting ENP4LED in
EEPROM to 0. In UTP applications, this bit should be set to 1.
All LED pins are dual function pins: input operation for configuration upon reset, and output operation
for LED after reset. If the pin input is floating upon reset, the pin output is active low after reset.
Otherwise, if the pin input is pulled down upon reset, the pin output is active high after reset.
Exception: Bi-color Link/Act mode of pin LED_ADD[4:0] when LEDMode[1:0]=10.
Below is an example circuit for LEDs. The typical values for pull-down resistors are 10KΩ.
Floating
3.3V
330 ohm
Pull Down
RTL8305SC
LED Pin
10K ohm
330 ohm
RTL8305SC
LED Pin
Figure 21. Floating and Pull-Down of LED Pins
For two-pin Bi-color LED mode (LEDMode[1:0]=10), Bi-color Link/Act (pin LED_ADD) and Spd (pin
LED_SPD) can be used for one Bi-color LED package, which is a single LED package with two LEDs
connected in parallel with opposite polarity. When LEDMode[1:0]=10, the active status of LED_ADD is
the opposite of LED_SPD.
Indication
No Link
100M Link
10M Link
100M Act
10M Act
Table 150. Spd and Bi-Color Link/Act Truth Table
Bi-Color State
Both Off
Green On
Yellow On
Green Flash
Yellow Flash
Spd: Input=Floating, Active Low.
Bi-color Link/Act: The active status
of LED_ADD is the opposite of
LED_SPD and does not interact with
input upon reset.
Spd
Link/Act
1
1
0
1
1
0
0
Flash
1
Flash
Spd: Input=Pull-down, Active High.
Bi-color Link/Act: The active status
of LED_ADD is the opposite of
LED_SPD and does not interact with
input upon reset.
Spd
Link/Act
0
0
1
0
0
1
1
Flash
0
Flash
5-port 10/100Mbps Single-Chip Dual MII Switch Controller 130
Track ID: JATR-1076-21 Rev. 1.2