USB2517 datasheet(18/58 Pages) MICROCHIP

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USB2517/USB2517I

DS00001598B-page 18

 2013-2016 Microchip Technology Inc.

Figure 6-1 shows a simple example of how this LED circuit will be implemented. The circuit should be replicated for each

of the 7 LED pins on the HUB. In this circuit, when the LED pin is driven to a logic low state, the Green LED will light up.

When the LED pin is driven to a Logic High state the Red LED will light up. When a 1 KHz square wave is driven out on

the LED pin, the Green and Red LED's will both alternately light up giving the effect of the color Orange. When nothing

is driven out on the LED pin (i.e. the pin floats to a "tri-state" condition), neither the Green nor Red LED will light up, this

is the "Off" state.

The assignment is as follows:

• LED_A1_N = LED D1 (Downstream Port 1)

• LED_A2_N = LED D2 (Downstream Port 2)

• LED_A3_N = LED D3 (Downstream Port 3)

• LED_A4_N = LED D4 (Downstream Port 4)

• LED_A5_N = LED D5 (Downstream Port 5)

• LED_A6_N = LED D6 (Downstream Port 6)

• LED_A7_N = LED D7 (Downstream Port 7)

The usage is as follows:

• LED_Ax_N Driven to Logic Low = LS device attached (Green LED)

• LED_Ax_N Driven to Logic High = FS device attached (Red LED)

• LED_Ax_N Pulsed @ 1 KHz= HS device attached (Orange color by pulsing Red & Green).

• LED_Ax_N is tri-state= No devices are attached, or the hub is in suspend, LED's are off.

FIGURE 6-1:

DUAL COLOR LED IMPLEMENTATION EXAMPLE

Hub LED pin

D1A (Green LED)

D1B (Red LED)

3.3V

General

Purpose

Diode

Current limiting

resistor

Connect to other

dual color diodes.

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