I2C NavKey – 7 Function Joypad (Black) Duppa

DESCRIPTION

The I2C NavKey is a perfect solution to make a perfect HMI without using precious resources.

The I2CNavKey is a small board that includes a 7 functions joypad. The joypad has 4 directional keys plus a central button and a rotary ring. It is controllable with the I2C bus, and it’s possible to configure 16 different I2C addresses. The I2CNavKey has also 3 configurable GPIOs with the same footprint as an RGB LED. These 3 GPIOs can be configured independently in 4 different ways: input, output, PWM and analogue input. Since the I2CNavKey is an I2C slave, it has a series of 8-bit registers where it’s possible to configure different parameters, it’s also possible to detect when the buttons are pressed or when the ring is rotated. It also has an open-drain output pin used as an interrupt output. This pin is used to notify the master when some event happens in the I2CNavKey, the source of the interrupt can be customized. Last but not least, it has also 256 bytes of EEPROM.

The I2C NavKey has 4 directional keys plus a central push button. It’s possible to detect when the keys are pressed and when released, the central push button can be detected also when it is double pushed.

The I2C NavKey has also central wheel that can be rotated left and right. It’s possible to read the central wheel in the same way as the I2C Encoder V2, there are 4 registers:

• CVAL: Current value of the Encoder.This value changes every time the encoder rotates.
• CMAX: Maximum value that CVAL can reach
• CMIN: Minimum value that CVAL can reach
• ISTEP: How much the CVAL has to increment at each and every encoder step.

These 4 registers can be 32bit signed int, or as float numbers IEEE 754.

FEATURES

• I2C bus works up to 400kHz
• Possibility to add the pull-up resistors on the I2C bus.
• Possibility to customize the I2C address by soldering the 4 SMD jumpers
• Open-drain Interrupt output pin, so no need to continuously poll the devices
• There is a 5 pin JST-XH header
• There are 3 General Purpose pins. (GP pins)
• 256 byte of internal EEPROM divided into 2 banks of 128 byte
• Voltage range is 2.5V to 5V
• Dimension of the device is 42.5×42.5mm or 1.67×1.67in
• 4 mounting holes with 3mm diameter
• Open source firmware

PIN	I/O Type	Function
GND	Power	Ground reference for logic
VCC	Power	Positive supply for logic
SDA	I/O	I2C Data
SCL	I	I2C Clock
INT	OD	Open-drain interrupt output

The I2C NavKey is powered by the MCU PIC16F18345. Inside of this MCU, there is a specific firmware that takes care of the functionality of the I2C NavKey and also the I2C communication with the external world. The I2C NavKey has several registers where is’t possible to configure the board. E.g. detect when a key is pressed etc. All the functionalities are described in the datasheet.

Address Range	Name	Description	Dimension	Default Value
0x00	GCONF	General Configuration	1 Byte	0
0x01	GP1CONF	GP 1 Configuration	1 Byte	0
0x02	GP2CONF	GP 2 Configuration	1 Byte	0
00×03	GP3CONF	GP 3 Configuration	1 Byte	0
0x04 – 0x05	INTCONF	INT pin Configuration	2 Byte	0
0x06 – 0x07	ISTATUS	Interrupt Status	2 Byte	0
0x08	I2STATUS	Secondary Interrupt Status	1 Byte	0
0x09	FSTATUS	Fade Process Status	1 Byte	0
0x0A – 0x0D	CVAL	Counter Value	4 Byte	0
0x0E – 0x11	CMAX	Counter Max Value	4 Byte	0
0x12 – 0x15	CMIN	Counter Min Value	4 Byte	0
0x16 – 0x19	ISTEP	Increment Step Value	4 Byte	1
0x1A	GP1REG	I/O GP1 Register	1 Byte	0
0x1B	GP2REG	I/O GP2 Register	1 Byte	0
0x1C	GP3REG	I/O GP3 Register	1 Byte	0
0x1D	DPPERIOD	Double Push Period	1 Byte	0
0x1E	FADEGP	Fade Timer Step of GP Ports	1 Byte	0
0x1F	GAMMAGP1	Gamma Correction on PWM of GP1	1 Byte	0
0x20	GAMMAGP2	Gamma Correction on PWM of GP2	1Byte	0
0x21	GAMMAGP3	Gamma Correction on PWM of GP3	1 Byte	0
0x7E	IDCODE	I2CNavKey Unique Code	1 Byte	0x5B
0x7F	VERSION	I2CNavKey Version	1 Byte	0x11
0x80 – 0xFF	EEPROM	EEPROM Memory	128 Byte	0

There are also 3 configurable GPIOs organized with the same footprint of an RGB LED. They are called GP1, GP2, and GP3. Possible Configuration

• PWMIn this way, you can add an RGB LED.
• AnalogThe pins are connected to the internal ADC of the PIC. In this way, you can add sensors or potentiometer according to your project needs
• OutputYou can use the pins as standard digital output
• InputYou can use the pins as standard digital input. Plus you can configure also the interrupt on the edges

In case of usage as PWM, there is also the possibility to enable the gamma correction. There are 8 type of gamma corrections: Gamma1 (linear), 1.8, 2.0, 2.2, 2.4, 2.6 and 2.8.

The I2C NavKey has an external interrupt, the INT pin, that became low when some event occurs. The event source is configurable in the configuration register. The INT pin is open drain, this means that a pull-up resistor is required. The I2C NavKey has an internall pull-up that can be activated.

RESOURCES

• Project
• Arduino Library