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1300 Henley Court Pullman, WA 99163 509.334.6306 www.digilentinc.com PmodJSTK2 Reference Manual Revised July 19, 2016 This manual applies to the PmodJSTK2 rev. C Overview The Digilent PmodJSTK2 (Revision C) is a versatile user input device that can be easily incorporated into a wide variety of projects. With a two-axis joystick on a center button, a trigger button, and a programmable RGB LED capable of 24-bit color. Features include: Factory Calibrated Two Axis Resistive Joystick Center Joystick Button Trigger Style Push Button 24-bit RGB LED 6-pin Pmod connector with SPI interface Library and example code available in resource center The PmodJSTK2. 1 Functional Descriptions The PmodJSTK2 utilizes two potentiometers oriented orthogonally to one another and are manipulated by moving the joystick in the X and Y directions. As the joystick moves, the voltage output at the sweep pin of each potentiometer changes and is measured by the 10-bit ADC present on the embedded PIC16F1618 microcontroller. The raw measured data is stored at a rate of 100 Hz as a 16-bit right-justified variable in RAM with the upper 6 bits masked with zeros. Additionally, each successive measurement also produces two 8-bit values representative of the joysticks physical location with respect to each axis. Note that if inversion of either of the 8-bit position axis are set, the values will not change until the data has been re-collected by the PIC16 at the 100 Hz rate. Copyright Digilent, Inc. All rights reserved. DOC : 502-330 Page 1 of 9 Other product and company names mentioned may be trademarks of their respective owners. PmodJSTK2 Reference Manual 2 Specifications 1 Parameter Min Typical Max Units Recommended Operating Voltage 3.1 3.3 3.5 V Maximum Supply Voltage - - 5.5 V 2 Power Supply Current - 4.85 - mA 3 Power Supply Current - 17.6 - mA Parameter Value Units Maximum Joystick Angle 25 Degrees Communication Protocol SPI Note: Data in the Typical Column uses VCC at 3.3V unless otherwise noted Note: Normal operation with the RGB LED Off and no buttons pressed Note: Normal operation with the RGB LED set to white and both buttons pressed 3 Interfacing with the Pmod The PmodJSTK2 communicates with the host board via the SPI protocol. With the PmodJSTK2, there are two types of data packet protocols: the standard data packet of 5 bytes and an extended data packet with 6 or 7 bytes in total. With the standard 5 byte protocol, users may use the old code from the PmodJSTK without any syntax errors. The 5 byte packet structure is provided in the image below: As noted in the standard data packet structure, users may either send a zero and a series of 4 dummy bytes to receive the standard 5 bytes of data or they may send a single command byte with up to 4 parameters in the four following bytes to set the internal values such as the joystick calibration or on-board RGB LED. The extended data protocol allows for additional data to be obtained from the device during a communication session after the standard 5 bytes of information such as normalized 8-bit positional data for each axis. Users may also obtain the current calibration values and the status of the module through this method. Copyright Digilent, Inc. All rights reserved. Page 2 of 9 Other product and company names mentioned may be trademarks of their respective owners.