Matrix - Joystick

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1 Introduction

Joystick

• The matrix-joystick module is a two-axis stick module. It consists of two Sliding rheostats and one button. It has two analog outputs and one digital output. Its positional states can be measured as X and Y axis values as the calibrated resistance of the two potentiometers.
• When you move the joystick the sliding rheostats' resistance will change and the corresponding x/y values will change too. When you push the joystick the SW level will turn low.

2 Features

• X and Y axis, and one button
• 2.54mm spacing pin
• PCB dimension(mm): 24 X 32

• Pin Description:

Pin	Description
GND	Ground
5V	Power 5V
SW	Button
X	X Axis
Y	Y Axis

3 Basic Device Operation

• It has two analog outputs and one digital output. The two analog outputs are measured as X and Y values as the calibrated resistance of the two potentiometers. The digital output is measured as Z value indicating whether or not the button is pressed.
  
• We extend all three outputs: X, Y and Z and users can use them easily.

4 Download Matrix Source Code

All the matrix modules' code samples are open source. They are maintained on GitHub - git://github.com/friendlyarm/matrix.git
Each branch in this hub contains the matrix modules' code samples for a board that the matrix modules can work with.

• The nanopi branch contains the matrix modules' code samples for the NanoPi
• The tiny4412 branch contains the matrix modules' code samples for the Tiny4412
• The raspberrypi branch contains the matrix modules' code samples for the RaspberryPi

Please follow the steps below to get the source code:
Install the git utility on a PC running Ubuntu14.04

$ sudo apt-get install git

Clone the matrix code from GitHub

$ git clone git://github.com/friendlyarm/matrix.git

If this is successful a "matrix" directory will be generated, which will contain all the matrix modules' code samples.

5 Connect to NanoPi

5.1 Preparations

Please install a Debian on a NanoPi and an appropriate cross compiler on a PC. Please refer to wiki: NanoPi
Compile a NanoPi kernel. Note: please use the kernel's source code from the nanopi-v4.1.y-matrix branch.

$ git clone https://github.com/friendlyarm/linux-4.x.y.git
$ cd linux-4.x.y
$ git checkout nanopi-v4.1.y-matrix
$ make nanopi_defconfig
$ touch .scmversion
$ make

5.2 Hardware Connection

Please refer to the following connection diagram to connect the Matrix-Joystick and Matrix-Analog_to_Digital_Converter to the NanoPi

Connection Details:

Matrix-Joystick
GND	NanoPi Pin14
5V	NanoPi Pin2
SW	Matrix-Analog_to_Digital_Converter A2
X	Matrix-Analog_to_Digital_Converter A1
Y	Matrix-Analog_to_Digital_Converter A0

5.3 Compile Test Program

Please login the matrix hub and enter the nanopi branch

$ cd matrix
$ git checkout nanopi

Compile the matrix code

$ make CROSS_COMPILE=arm-linux- clean
$ make CROSS_COMPILE=arm-linux-
$ make CROSS_COMPILE=arm-linux- install

Note: please make sure to install the cross compiler "arm-linux-gcc-4.4.3" on your PC, which is used to compile files for the NanoPi-Debian.
Generated library files are under the "install/lib" directory. Applications are under the "install/usr/bin" directory. The test program for the "Matrix-Joystick" module is "matrix-joystick".

5.4 Run Test Program

Please copy the library files and test program to the NanoPi

$ cp install/usr/bin/* nanopi_rootfs/usr/bin/
$ cp install/lib/* nanopi_rootfs/lib/ -d

Power on the NanoPi and run the following command in Debian's terminal

$ matrix-joystick

5.5 Code Sample

int main(int argc, char ** argv)
{
	int mode = 0x0;
 
	if ((devFD = pcf8591Init()) == -1) {
        printf("Fail to init pcf8591 AD\n");
        return -1;
    }
    if (pcf8591SetCtrl(devFD, PCF8591_INIT_AD_CONTROL) == -1) {
        printf("Fail to Set pcf8591 control AD\n");
        pcf8591DeInit(devFD);
        return -1;
    }
 
    int i = 0;
	int x, y, z;
	signal(SIGINT, PS2Handler);
	for (i=0; i<PS2_READ_TIMES; i++) {
		x = pcf8591Read(devFD, mode, PCF8591_AIN_CHANNEL0);
		y = pcf8591Read(devFD, mode, PCF8591_AIN_CHANNEL1);
		z = pcf8591Read(devFD, mode, PCF8591_AIN_CHANNEL2);
		if (z > SW_TRIGGER) {
			z = 0;
		} else {
			z = 1;
		}
		printf("X=%3d Y=%3d Z=%d\n", x, y, z);
		sleep(1);
	}
	pcf8591DeInit(devFD);
	return 0;
}

6 Connect to Tiny4412

6.1 Preparations

Please refer to the Tiny4412's user's manual to install a UbuntuCore on the Tiny4412 and install an appropriate cross compiler on a PC.
Note: only the Tiny4412SDK-1506 carrier board can work with this module.

6.2 Hardware Connection

Please refer to the following diagram to connect the Matrix-Joystick and Matrix-Analog_to_Digital_Converter to the Tiny4412

Connection Details:

Matrix-Joystick
GND	Tiny4412 CON16 GND
5V	Tiny4412 CON16 5V
SW	Matrix-Analog_to_Digital_Converter A2
X	Matrix-Analog_to_Digital_Converter A1
Y	Matrix-Analog_to_Digital_Converter A0

6.3 Compile Test Program

Please login the Matrix hub and enter the matrix-tiny4412 branch

$ cd matrix
$ git checkout tiny4412

Compile the matrix code

$ make CROSS_COMPILE=arm-linux-gnueabihf- clean
$ make CROSS_COMPILE=arm-linux-gnueabihf-
$ make CROSS_COMPILE=arm-linux-gnueabihf- install

Note: please make sure to install the cross compiler "arm-linux-gnueabihf-gcc-4.7.3" on your PC, which is used to compile files for the Tiny4412-UbuntuCore.
Generated library files are under the "install/lib" directory. Applications are under the "install/usr/bin" directory. The test program for the "Matrix-Joystick" module is "matrix-joystick".

6.4 Run Test Program

Please copy the library files and test program to the Tiny4412

$ cp install/usr/bin/* tiny4412_rootfs/usr/bin/
$ cp install/lib/* tiny4412_rootfs/lib/ -d

Power on the Tiny4412 and run the following command in UbuntuCore's terminal

$ matrix-joystick

6.5 Code Sample

int main(int argc, char ** argv)
{
	int mode = 0x0;
 
	if ((devFD = pcf8591Init()) == -1) {
        printf("Fail to init pcf8591 AD\n");
        return -1;
    }
    if (pcf8591SetCtrl(devFD, PCF8591_INIT_AD_CONTROL) == -1) {
        printf("Fail to Set pcf8591 control AD\n");
        pcf8591DeInit(devFD);
        return -1;
    }
 
    int i = 0;
	int x, y, z;
	signal(SIGINT, PS2Handler);
	for (i=0; i<PS2_READ_TIMES; i++) {
		x = pcf8591Read(devFD, mode, PCF8591_AIN_CHANNEL0);
		y = pcf8591Read(devFD, mode, PCF8591_AIN_CHANNEL1);
		z = pcf8591Read(devFD, mode, PCF8591_AIN_CHANNEL2);
		if (z > SW_TRIGGER) {
			z = 0;
		} else {
			z = 1;
		}
		printf("X=%3d Y=%3d Z=%d\n", x, y, z);
		sleep(1);
	}
	pcf8591DeInit(devFD);
	return 0;
}