Library Description

The library initializes and defines I2C bus driver and driver functions which offer a choice to write data in the registers and to read data from the registers. The library also offers a choice to detect touch on enabled sensor inputs in two possible modes, Active and Standby mode.
Every sensor input can be configured to work in both modes at the same time (Combo mode). The sensor inputs can also be configured to detect when touch is released and can generate an interrupt as long as the touch is detected. For more details check the documentation.

Key functions:

void touchkey4_writeReg( const uint8_t register_address, const uint8_t transfer_data ) - The function writes one-byte data in the register.

void touchkey4_readReg( const uint8_t register_address, uint8_t *dataOut, const uint8_t nBytes ) - The function reads data from the register.

void touchkey4_detectTouch( uint8_t *inputSens ) - The function detects touch on the sensor inputs and checks if touch is detected or if touch is released.

void touchkey4_setComboMode( const uint8_t analogGain, const uint8_t enInput1, const uint8_t enInput2, const uint8_t enInput3 ) - Function puts the device in Combo mode (Active and Standby) and enables desired inputs in Active mode, Standby mode or both modes.

Examples Description

• System Initialization - Initializes peripherals and pins.
• Application Initialization - IInitializes I2C driver and sets configuration for TouchKey 4 click. TouchKey 4 is configured to works in Combo mode (Active and Standby mode). Input 1 is enabled in Active mode, input 3 is enabled in Standby mode, and input 2 is enabled to works in both modes. In this example, the interrupt will be generated when touch is detected and when touch is released. Also, input 2 will generate an interrupt as long as the touch is detected (press and hold the event), while input 1 and input 3 will generate interrupt only once on one touch detection, after which the touch will be released. Note: Standby mode should be used when fewer sensor inputs are enabled, and when they are programmed to have more sensitivity.
• Application Task - (code snippet) - Calls function to check touch detection (is interrupt occurred) and shows a message on USB UART if touch is detected or if touch is released on enabled inputs.

void applicationTask()
{
 touchkey4_detectTouch( &sensorResults[0] );
 for (cnt = 0; cnt < 3; cnt++)
 {
 if (sensorResults[ cnt ] == 1)
 {
 if (cnt == 0)
 mikrobus_logWrite( "Input 1 is touched", _LOG_LINE );
 else if (cnt == 1)
 mikrobus_logWrite( "Input 2 is touched", _LOG_LINE );
 else
 mikrobus_logWrite( "Input 3 is touched", _LOG_LINE );
 }
 else if (sensorResults[ cnt ] == 2)
 {
 if (cnt == 0)
 mikrobus_logWrite( "Input 1 is released", _LOG_LINE );
 else if (cnt == 1)
 mikrobus_logWrite( "Input 2 is released", _LOG_LINE );
 else
 mikrobus_logWrite( "Input 3 is released", _LOG_LINE );
 mikrobus_logWrite( "", _LOG_LINE );
 }
 }
}

Other mikroE Libraries used in the example:

• I2C
• UART

Additional notes and information

Depending on the development board you are using, you may need USB UART click,  USB UART 2 click or RS232 click to connect to your PC, for development systems with no UART to USB interface available on the board. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.