CCS/CC2650MODA: Pin interrupt trigger for pin with in and out buffer enabled

Tool/software: Code Composer Studio

I have couple of questions regarding CC2650 and TI RTOS:

1. I need to use a pin as input and output simultaneously in an open drain mode (externally pulled high) to do a one-wire interface. But I am having hard time getting an interrupt when pin is pulled low. Is it possible to get a negative edge interrupt when a pin is configured with input enabled, output enabled, no pullup and open drain?

"Board_ONE_WIRE | PIN_INPUT_EN | PIN_GPIO_OUTPUT_EN | PIN_NOPULL | PIN_OPENDRAIN,"

2. For a Timer is it possible to configure to trigger timer start on falling edge of a pin, set a compare register value to stop timer and generate an interrupt on matching compare value? Base on CC2650 reference manual it don't seem to be possible.

/*********************************************************************
 * @fn      edgeTriggerCallback
 *
 * @brief
 *
 * @param   none
 *
 * @return  none
 */
void edgeTriggerCallback(PIN_Handle handle, PIN_Id pinId) {

    //do something....
}


/*********************************************************************
 * @fn      OneWire_processEvent
 *
 * @brief   
 *
 * @param   none
 *
 * @return  none
 */
static void OneWire_taskFxn(UArg a0, UArg a1)
{
  PIN_State  hStateHui;
  PIN_Handle hPin;

  // Initialize application
  OneWire_init();

  // Define pins used by Human user interface and initial configuration
  const PIN_Config aPinListHui[] = {
    Board_RLED      | PIN_GPIO_OUTPUT_EN | PIN_GPIO_LOW | PIN_PUSHPULL | PIN_DRVSTR_MAX,
    Board_ONE_WIRE  | PIN_INPUT_EN | PIN_GPIO_OUTPUT_EN | PIN_NOPULL | PIN_OPENDRAIN,    
    PIN_TERMINATE
  };

  // Get handle to this collection of pins
  hPin = PIN_open(&hStateHui, aPinListHui);
  if (!hPin) {
      // Handle allocation error
  }

  // Edge trigger config
  PIN_registerIntCb(hPin,  edgeTriggerCallback);
  PIN_setInterrupt(hPin,  PIN_ID(Board_ONE_WIRE)| PIN_IRQ_NEGEDGE);



  // Application main loop
  for (;;)
  {
    // Get the ticks since startup
    uint32_t tickStart = Clock_getTicks();

    PIN_setOutputValue(&hStateHui, Board_RLED, PIN_getOutputValue(Board_RLED) ^ 0x0001);

    // Sleep for 250 ms
    Task_sleep(250000/10);
    //printf("OneWire_taskFxn\r\n");

  }
}