Hardware

© 2010-2011 Microchip Technology Inc.

DS51936B-page 17

2.2.5

Switches

Push button switches (SW1, SW2 and SW3) provide the following functionality:

• SW1: Active-low switch connected to RD6

• SW2: Active-low switch connected to RD7

• SW3: Active-low switch connected to RD13

The switches do not have any debounce circuitry and require the use of software

debounce techniques. When idle, the switches are pulled high (+3.3V). When pressed,

they are grounded.

2.2.6

LEDs

The LEDs (LED1, LED2 and LED3) are connected to PORT D of the processor:

• LED1: Active-high LED connected to RD0

• LED2: Active-high LED connected to RD1

• LED3: Active-high LED connected to RD2

The corresponding PORT D pins must be configured as digital outputs and set high in

order to turn on the LEDs.

2.2.7

Oscillator Options

The installed DSC or MCU has an 8 MHz crystal (Y3) connected to it. This crystal is

used by the microcontroller’s Primary Oscillator. Use of the external crystal is required

in order to develop USB applications, as the USB specification dictates a frequency tol-

erance of ± 0.25% for full speed. Non-USB applications can use the internal oscillators

if preferred. The starter kit also has provisions for an external Secondary Oscillator

(Y2); however, the crystal for this oscillator is not populated.

The PIC24FJ256GB106 device is independently clocked and has its own 12 MHz

crystal (Y1).

2.2.8

120-pin Modular Expansion Connector

The dsPIC33E or PIC24E USB Starter Kit includes a 120-pin modular expansion

interface (Application Board Connector J3) on its bottom side. This allows the board to

be optionally used in conjunction with other Microchip development boards such as the

I/O Expansion Board or the Multimedia Expansion Board (MEB), thereby extending the

functionality provided by the starter kit.

TABLE 2-1:

STARTER KIT CONNECTOR PART NUMBERS

Connector

HIROSE Electric P/N

Starter Kit Connector

FX10A-120P/12-SV1(71)

Application Board Connector

FX10A-120S/12-SV(71)