4.1 Basic Connection Requirements

Getting started with the PIC18-Q20 family of 8-bit microcontrollers requires attention to a minimal set of device pin connections before proceeding with development.

The following pins must always be connected:

• All V_DD and V_SS pins (see the Power Supply Pins section)
• MCLR pin (see the Master Clear (MCLR) Pin section)

These pins must also be connected if they are being used in the end application:

• ICSPCLK/ICSPDAT pins used for In-Circuit Serial Programming™ (ICSP™) and debugging purposes (see the In-Circuit Serial Programming (ICSP) Pins section)
• OSCI and OSCO pins when an external oscillator source is used (see the External Oscillator Pins section)

Additionally, the following pins may be required:

• V_REF+/V_REF- pins are used when external voltage reference for analog modules is implemented

The minimum mandatory connections are shown in the figure below.