Digilent 6021-210-000P-KIT - Manual (Page 17)

Universal Development Board™ Reference Manual
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Page 17 of 27
The SPI EEPROM is wired directly to the PIM bus. To use it from a DIP device in one of the DIP sockets, it is
necessary to use jumper wires from the DIP bus header to the PIM bus header to connect the appropriate DIP
microcontroller pins to the above noted signals on the PIM bus. When doing this, ensure that there is no PIM
installed in the PIM socket and that the on-board PIC32MX360 is disabled by removing the shorting block from the
PIC32 Enable jumper.
11 User I/O Devices
The USB features two potentiometers, three push button switches and eight discrete LEDs to provide on-board I/O
user I/O devices. These devices are not pre-wired to any microcontroller pin position, and jumper wires are used to
attach them to the desired microcontroller pin for the device being used. The connection points for these on-board
I/O devices appear on connector J3. Connector J3 also provides access to the VCC3V3 bus and the GND bus for
connection to external circuits.
11.1 Analog Input (Potentiometer)
There are two 10kΩ potentiometers located at R33 and R35 on the UDB. These pots are connected to the PIM
headers at J3. The Header at J3 marks the pin for POT1 and POT2 on the board. The maximum value of the
potentiometers is reached by rotating to the left position. When the POT is rotated to the right, lower values are
reached until minimum at the far right position. A 1K ohm resistor is provided in series with the wiper of each
potentiometer to protect against hard shorts to VCC3V3 or GND when the wipers are at either end of their
rotation.
Refer to Appendix B: User I/O Devices for a table showing the layout of header J3.
11.2 Switches
Three push button switches: BTN0, BTN1, and BTN3 are provided. These buttons are active high. The output pins
are pulled to ground through 20K ohm when the button is not pressed, and are pulled to VCC3V3 through 10K ohm
when the button is pressed. The BNT0, BNT1, and BTN3 positions are labeled on the board at connector J3.
11.3 LEDs
There are eight user I/O LEDs on the UDB. The LEDs are located at LD0 through LD7 which are connected to the
PIM headers of J3. Each LED pin on PIM header J3 is marked on the PCB. The pins are set to low to light each LED
and high to turn each LED off.