File content as of revision 8:dd258f9e24b0:

/* Keyboard chip TCA8418 control */
#include "mbed.h"
#include "keyboard.h"

extern int key_hit_ID;
//extern mbos CDU_OS;

//CDU Keyboard communications KEYBOARD_INT
InterruptIn CDU_KB_INT( p5 );  //Set CDU keyboard interrupt line. 
I2C CDU_I2C(p28, p27);          //I2C bus for keyboard/temp chip.

//CDU Keyboard LEDS
DigitalOut EXEC( p12 );
DigitalOut FAIL( p17 );
DigitalOut DSPY( p18 );
DigitalOut  MSG( p19 );
DigitalOut OFST( p20 );

//CDU background lighting
AnalogIn BGL_POT( p16 ); //background light control potmeter
PwmOut BGL_LED( p21 );   //PWM output background lighting

void CDU_KB_COMM_INIT()
{   //initialize communication with TCA84818
    CDU_I2C.write(CDU_KB_WRITE); //initiate write cycle
    //intialize all registers from TCA8418 here
    CDU_I2C.read(CDU_KB_READ); //start reading from TCA4818
}

void CDU_KB_GET_KEY()
{
    CDU_I2C.write(CDU_KB_READ); //initiate read cycle
    key_hit_ID = CDU_I2C.read(CDU_KB_READ)  ;    //read key value
    //CDU_OS.SetEvent(KEY_EVENT,SEND_KEYMESSAGE_TASK_ID ); //Set event key to wakeup task
    } 

void CDU_KB_INT_START()
{
    CDU_KB_INT.mode( PullUp );          //Keyboard chip pulls this line to 0 on a keypress
    CDU_KB_INT.fall(&CDU_KB_GET_KEY);   //Bind function to interrupt handler
    }

void CDU_SET_BGL_INTENSITY( int nVal=255 )
{
    //This routine must be called 5-10x per second. Manual test to see what is pleasant to see
    //AnalogIn BGL_POT( p15 ); //background light control potmeter. Returns a value between 0.0 and 1.0
    //PwmOut BGL_LED( p21 );   //PWM output
    //calculate required brightness in percentage from 0%-100%
    //nVal 255     --> calculate brightness from potmeter value (default value if no parameter is passed)
    //nVal = 0     --> switch off backlight
    //nVal = 100   --> switch on backlight max

    switch (nVal) 
    {
        case 0:
        {
            //switch off backlighting
            BGL_LED.pulsewidth( 0.0 );
            break;
        }
        case 100:
        {
            //switch on backlighting
            BGL_LED.pulsewidth( 100.0 );
            break;
        }
        case 255:
        {
            //calculate percentage from potmeter value
            BGL_LED = ( 0.0 + 100*BGL_POT );
        }
    }
}