User manual

DS40001812A-page 34  2015 Microchip Technology Inc.
Explorer 8 Development Board User’s Guide
A.1.4 Micro USB Port
A micro USB port is provided not just for powering the board but also for
communications between the device and a host PC via USB. The micro USB cable
included in the Explorer 8 Development Board Kit can be used to connect the board’s
micro USB port to the host PC’s USB port.
The on-board MCP2221 is a USB-to-UART/I
2
C serial converter that enables USB
connectivity for devices with UART or I
2
C interfaces.
A.1.5 Switches
Three switches are provided on the board:
• S1 – Active-low switch connected to RB0
• S2 – Active-low switch connected to RA5
• S3 – MCLR
to hard reset the processor
When pressed, the switches are grounded. When idle, they are pulled high (V_VAR).
A.1.6 Oscillator Options
An 8 MHz crystal (Y1) serves as the controller’s primary oscillator. It can also be used
as TMR0’s clock source for some devices depending upon the configured J36 and J37
settings.
A.1.7 Analog Input (Potentiometer)
A 10 kΩ potentiometer (R25) is connected through a series resistor to RA0/AN0.
The potentiometer can be adjusted from V_VAR to GND to provide an analog input to
one of the device ADC channels.
A.1.8 ICD Connector
The MPLAB
®
ICD 3 can be connected to the modular connector (J26) for programming
and in-circuit debugging. Jumpers J51 and J52 define the connection of the in-circuit
debugger to the device pins. The MPLAB REAL ICE can also be connected to this
interface.
A.1.9 PICkit
™
Connector
A PICkit 3 In-Circuit Debugger/Programmer can be connected to the 6-pin interface
provided by J12. Jumpers J51 and J52 define the connection of the PICkit3 to the
microcontroller pins.
Note: For details on this connection, see Section 2.4 “Connecting to Host PC
for USB Communication”
.
Note: For details, see Section Section 2.3.3 “Programming the
Microcontroller”
.
Note: For details, see Section 2.4 “Connecting to Host PC for USB
Communication”
.