4.1 Basic Connection Requirements
Getting started with the PIC18-Q71 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 VDD and VSS 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:
- VREF+/VREF- pins are used when external voltage reference for analog modules is implemented
 
The minimum mandatory connections are shown in the figure below.
