10MHz crystal oscillator. We carefully chose the most convenient crystal value that provides clock frequency which can be used directly, or with the PLL multipliers and dividers to create higher MCU clock value.
VCAP jumper. Some PIC18FK and all PIC18FJ microcontrollers have cores that work on 1.8V-2.5V voltage range, and peripherals that work with 3.3V and 5V voltages. Internally, those microcontrollers have power regulators which adjust the core voltage levels. In order for those devices to have a stable operation of the core, manufacturer recommends that decoupling capacitive filters should be provided, and connected between specific microcontroller pins designated with VCAP and GND. This MCU card provides a VCAP jumper which is used for this purpose. Jumper is placed by default.
USB communication lines. These two jumpers, when in USB position, connect D+ and D- lines of the on-board USB connector with RF3 and RF4 microcontroller pins. Since PIC18F8520 doesn’t support USB, jumpers are in I/O position.
VUSB line jumper. For PIC18F8xJ5x devices, this jumper should be connected to VCC for enabling internal USB controller. Since PIC18F8520 doesn’t support USB, this jumper is in I/O position.
ENVREG selection jumper. PIC18FJ and PIC18FK microcontrollers are using internal voltage regulator which is enabled by placing

IR Gesture 2 Click
RS232 3 Click
Clicker 4 Inverter Shield
3D Hall 11 Click
Accel 4 Click
I2C MUX 6 Click
CLICKER 4 for TMPM4K
GNSS 15 Click
ADC 24 Click
ESP8684 Click
Pressure 19 Click
Red Pitaya Click Shield
ADC 18 Click
Pressure 20 Click
UNI-DS v8
HYDROGEN Click
Alcohol 3 Click
EXPAND Click
Accel Click
RN4678 Click
RTC Click
tRF Click
GSM Click
GSM/GNSS Click
MP3 Click
Headphone AMP 3 Click 