TCA8418E: TCA8418 stop to read keyboard

I have two IC on the same I2c network. The first is a PCA9685 PWM controller and the other is the TCA8418E. If I run the code for the on or the other, there is no problems. I can also run it in a mode, where, when I press a buttom I turn on a pwm output, and then on nest timer slot turn it of. 

The problem arise when I make it do a bit more. 

The timer is 10 ms. so when a key is pressed I turn the pwm to 100%. after 5 ticks I turn it dowm to 50% then 25 tick later I switch it of.

I can run for about 30-150 keypress, then the colums goes into a HI imp state

My theory is that i has to do with activ I2C bus and a interrupt fra a key.

When the interrupt comes frrom the tca8418 I just it a bit in software and wait to net timetick to handle it.

After it stops I can still read register of the TCA8418, and they are the same. It just stops reading. And if the colums are in HI imp, then it dont know the a key is pressed.

Here is how they look, when no key is pressed and when a key is pressed.

Normally it looks like this:

Schematic:

void TCA8418::initialize()
{
    //initialize communication with TCA84818
	i2c.frequency(100000);
    char cmd[2];
    cmd[0] = REG_CFG; //pointer byte to CFG register
    cmd[1] = 0x91; //data for CFG register KE_IEN set to 1
    if ( i2c.write(KB_BASEADRS,cmd, 2) == I2C_ACK ) { //initiate write cycle and check for ACK
        //intialize all registers from TCA8418 here
        cmd[0] = REG_INT_STAT; //pointer byte to Interrupt Status Register
        cmd[1] = 0x01; //Reset KE-INT flag
        i2c.write(KB_BASEADRS,cmd, 2 );  //Write to Interrupt Status Register from TCA4818

        //Set TCA8418 to Keypad mode
        cmd[0]=REG_KP_GPIO1; //KP_GIO1
        cmd[1]=0x0F; //Set to Keypad mode
        i2c.write(KB_BASEADRS,cmd, 2);

        cmd[0]=REG_KP_GPIO2; //KP_GIO2
        cmd[1]=0xFF; //Set to Keypad mode
        i2c.write(KB_BASEADRS,cmd, 2);

        cmd[0]=REG_KP_GPIO3; //KP_GIO3
        cmd[1]=0x00; //Set to Keypad mode
        i2c.write(KB_BASEADRS,cmd, 2);

        //Set TCA8418 to Keypad mode
        cmd[0]=REG_DEBOUNCE_DIS1; //KP_GIO1
        cmd[1]=0x0F; //Set to Keypad mode
        i2c.write(KB_BASEADRS,cmd, 2);

        cmd[0]=REG_DEBOUNCE_DIS2; //KP_GIO2
        cmd[1]=0xFF; //Set to Keypad mode
        i2c.write(KB_BASEADRS,cmd, 2);

        cmd[0]=REG_DEBOUNCE_DIS3; //KP_GIO3
        cmd[1]=0x00; //Set to Keypad mode
        i2c.write(KB_BASEADRS,cmd, 2);

    } else {
        //No response from TCA8418 keyboard chip
        // FAIL = 1; //Switch on FAIL indicator
    }
}

char TCA8418::GET_KEY()
{

    //  Key_led = !Key_led;  // : toggle LED 2

    char cmd[2];
    //Read interrupt status flag
    char key_hit_ID=0;

    ReadReg(REG_INT_STAT);

    while (ReadReg(REG_KEY_LCK_EC)) {	//Read Key Lock and Event Counter
	  key_hit_ID =  int(ReadReg(REG_KEY_EVENT_A)); //Keypress --> read data from keybuffer
	  if (key_hit_ID & 0x80) release=0; else release=1;
    }
    //Reset interrupt flag
    cmd[0] = REG_INT_STAT; //pointer byte to Interrupt Status Register
    cmd[1] = 0xFF; //Reset KE-INT flag
    i2c.write(KB_BASEADRS,cmd, 2);

  return key_hit_ID;
}