FORTH on Arduino -3- (Funduino Joystick game shield)

Having eForth running on my Arduino testing some I/O is what i wanted. Some years ago i posted https://blog.jeronimus.net/2017/04/funduino-joystick-shield.html about an Arduino joystick / button shield. This cheap shield has a joystick some input buttons. (And some connection headers that i did not use in this test.)  
There are several versions of this board. I have the Funduino V1.A The shield gives your Arduino the functionality found on the old Nintendo controllers. It can be used for gaming or control hardware.
2 analog inputs and some digital Ideal to start with this this shield with eForth to do some simple input tests. 

The table below lists how the buttons are connected to the Arduino 

Arduino	Button	Port&bit
D2	Key A UP	PD2
D3	Key B RIGHT	PD3
D4	Key C DOWN	PD4
D5	Key D LEFT	PD5
D6	Key E Start	PD6
D7	Key F Select	PD7
D8	Analog button	PB0
A0	AnalogX Joystick	Analog0
A1	AnalogY Joystick	Analog1

The ForthArduino1.pdf contains several I/O examples that can be tested with this board: 

For the analog ports
Paragraph 3.5 mentions
If you connect an external analog signal source to the A0 pin, then type the following commands to read its analog value:

27 C!    \ setup A0 as input pin, which is on PC-0 port
 1 28 C! \ turn on pull-up resister on A0 pin
40 7C C! \ setup reference and multiplexer inputs
C3 7A C! \ start conversion
78 ?     \ display results 78 = low byte 79 = high byte

Example for digital port  ( D8 PB0 button of joystick)

 0 24 C! \ make all Port B pins input
 1 25 C! \ turn on pull-up resistor for Line 8
23 C@  . \ read PINB port and show its contents

23 C@ . \ repeat with switch on and off

What i especially like about eForth on Arduino is that using the terminal you can interactively test and play with the system to adapt it to your own needs.
The AVR Family databook / ATmega328P datasheet contains detailed info about all the internal registers. Also the multiple functions of the pins are explained.
Also you can find the info that i summarized in the table below.

	Data register	Data direction  register	Input pin address
PortB	PORTB	DDRB	PINB
D8 Analog button	0x05 (0x25)	0x04 (0x24)	0x03 (0x23)
PortC	PORTC	DDRC	PINC
	0x08 (0x28)	0x07 (0x27)	0x06 (0x26)
PortD	PORTD	DDRD	PIND
D2-D7 Key A - F	0x0B (0x2B)	0x0A (0x2A)	0x09 (0x29)

For reading the other buttons you need to read portD.

 0 2B C! \ make all Port B pins input

FF 2A C! \ turn on pull-up resistor for all lines

29 C@ .  \ read PINB port and show its contents

Some simple words to play with the shield and print the output :

: .PD  0 2A C! FF 2B C! 29 C@ . ;              / Print PortD  ( Buttons)

: .PB  0 24 C!  1 25 C! 23 C@ . ;              / Print PortB ( Joystick button)
: .PX 27 C!  1 28 C! 40 7C C! C3 7A C! 78 ? ;  / Print Joystick X value

: .PY 27 C!  1 28 C! 41 7C C! C3 7A C! 78 ? ;  / Print Joystick Y value
: .JOY .PB .PX .PY ;                           / Print all Joystick values

I used short cryptic words like .PB. More descriptive would be .PrintPortB, For playing with the system it would require more typing more characters. 

In Forth it is also possible to change the output to binary to easy see the bits corresponding to each button:

2 BASE !   /  Set Binary output 

HEX        /  Set Hexadecimal output

Hope this Arduino Forth ( eForth) introductory blog article can be help others starting to use Forth on Arduino.

Funduino Joystick shield

Funduino Joystick shield

From Aliexpress i got a Arduino Gamepads JoyStick KeypadShield PS2  (I recently found it at another seller for 2,33 Euro ) 

Using Google i found out there are some different versions.

My shield  (V1.A ) uses the following connections

D2 Key A UP
D3 Key B RIGHT
D4 Key C DOWN
D5 Key D LEFT

D6 Key E Start
D7 Key F Select

D8 Analog button
A0 AnalogX Joystick
A1 AnalogY Joystick

There are some headers to get to the other Arduino pins.

Some headers are pre arranged for special interfaces (On my board I2C, Bluetooth, Nokia5110 display, nRF24L01)
A slide switch to select between 3V3 and 5V mode.
A red power led

TestScript

/*
JoystickArduinoBasicExample

A basic sketch to demonstrate reading values from the joystick shield

How to use:
* Connect joystick shield to your Arduino
* Upload this sketch to your Arduino
* Open the Arduino IDE Serial Monitor (set to 9600 baud)
* Waggle joystick, push buttons

Requires:
* Arduino
* Joystick Shield

April 2017 by JJ adapted version of a version
written for SparkFun Arduino Inventor's Kit CIRC-JOY
Based on original example by Ryan Owens
*/

// Store the Arduino pin associated with each input

const byte PIN_BUTTON_UP = 2;
const byte PIN_BUTTON_RIGHT = 3;
const byte PIN_BUTTON_DOWN = 4;
const byte PIN_BUTTON_LEFT = 5;

const byte PIN_BUTTON_START = 6;
const byte PIN_BUTTON_SELECT = 7;

const byte PIN_BUTTON_JOY = 8; // Select button is triggered when joystick is pressed
const byte PIN_ANALOG_X = 0;
const byte PIN_ANALOG_Y = 1;

void setup() {
Serial.begin(9600);
// Specify each pin connected to a pushbutton as an input.
// Also enable the Arduino's internal "pull-up" resistors
// for each pushbutton we want to read--this means the shield
// doesn't need to have resistors on it.
// Note that when a pull-up resistor is used on a pin the
// meaning of the values read are reversed compared to their
// usual meanings:

// * HIGH = the button is not pressed
// * LOW = the button is pressed

pinMode(PIN_BUTTON_RIGHT, INPUT);
digitalWrite(PIN_BUTTON_RIGHT, HIGH);

pinMode(PIN_BUTTON_LEFT, INPUT);
digitalWrite(PIN_BUTTON_LEFT, HIGH);

pinMode(PIN_BUTTON_UP, INPUT);
digitalWrite(PIN_BUTTON_UP, HIGH);

pinMode(PIN_BUTTON_DOWN, INPUT);
digitalWrite(PIN_BUTTON_DOWN, HIGH);

pinMode(PIN_BUTTON_START, INPUT);
digitalWrite(PIN_BUTTON_START, HIGH);

pinMode(PIN_BUTTON_SELECT, INPUT);
digitalWrite(PIN_BUTTON_SELECT, HIGH);

pinMode(PIN_BUTTON_JOY, INPUT);
digitalWrite(PIN_BUTTON_JOY, HIGH);
}

void loop() {
// Print the current values of the inputs (joystick and
// buttons) to the console.
Serial.print("l:");
Serial.print(digitalRead(PIN_BUTTON_LEFT));
Serial.print(" ");

Serial.print("r:");
Serial.print(digitalRead(PIN_BUTTON_RIGHT));
Serial.print(" ");

Serial.print("u:");
Serial.print(digitalRead(PIN_BUTTON_UP));
Serial.print(" ");

Serial.print("d:");
Serial.print(digitalRead(PIN_BUTTON_DOWN));
Serial.print(" / ");

Serial.print("g:");
Serial.print(digitalRead(PIN_BUTTON_START));
Serial.print(" ");

Serial.print("s:");
Serial.print(digitalRead(PIN_BUTTON_SELECT));
Serial.print(" / ");

Serial.print("j:");
Serial.print(digitalRead(PIN_BUTTON_JOY));
Serial.print(" ");

Serial.print("x:");
Serial.print(analogRead(PIN_ANALOG_X));
Serial.print(" ");

Serial.print("y:");
Serial.print(analogRead(PIN_ANALOG_Y));
Serial.print(" ");

Serial.println();
}

Links

• http://forum.arduino.cc/index.php?topic=266150.0

Video review

https://www.youtube.com/watch?v=wJXgECta8oc

Links to other version of this board

• https://www.sparkfun.com/products/9760
• https://www.elecfreaks.com/wiki/index.php?title=Joystick_Shield