TIVA TM4C129ENCPDT - how to configure Buffered version of 32.768 clock on RTCCLK on GPIO PIN

//*****************************************************************************
//
// TM4C129_HibernateClockOut.c - Example demonstrating how to configure the
//						TM4C129 Hibernate Clock Out on a Port Pin
//
// Copyright (c) 2014 Texas Instruments Incorporated.  All rights reserved.
// Software License Agreement
//
//   Redistribution and use in source and binary forms, with or without
//   modification, are permitted provided that the following conditions
//   are met:
//
//   Redistributions of source code must retain the above copyright
//   notice, this list of conditions and the following disclaimer.
//
//   Redistributions in binary form must reproduce the above copyright
//   notice, this list of conditions and the following disclaimer in the
//   documentation and/or other materials provided with the
//   distribution.
//
//   Neither the name of Texas Instruments Incorporated nor the names of
//   its contributors may be used to endorse or promote products derived
//   from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// This is part of revision 2.1.0.12573 of the Tiva Firmware Development Package.
//
//*****************************************************************************

#include <stdbool.h>
#include <stdint.h>
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "inc/hw_gpio.h"
#include "inc/hw_ints.h"
#include "inc/hw_uart.h"
#include "inc/hw_hibernate.h"
#include "driverlib/gpio.h"
#include "driverlib/pin_map.h"
#include "driverlib/sysctl.h"
#include "driverlib/uart.h"
#include "driverlib/hibernate.h"
#include "driverlib/interrupt.h"
#include "utils/uartstdio.h"

//*****************************************************************************
//
// System clock rate in Hz.
//
//*****************************************************************************
volatile uint32_t g_ui32SysClock;

//*****************************************************************************
//
// This function sets up UART0 to be used for a console to display information
// as the example is running.
//
//*****************************************************************************
void
InitConsole(void)
{
    //
    // Enable GPIO port A which is used for UART0 pins.
    // TODO: change this to whichever GPIO port you are using.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

    //
    // Configure the pin muxing for UART0 functions on port A0 and A1.
    // This step is not necessary if your part does not support pin muxing.
    // TODO: change this to select the port/pin you are using.
    //
    GPIOPinConfigure(GPIO_PA0_U0RX);
    GPIOPinConfigure(GPIO_PA1_U0TX);

    //
    // Enable UART0 so that we can configure the clock.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);

    //
    // Use the internal 16MHz oscillator as the UART clock source.
    //
    UARTClockSourceSet(UART0_BASE, UART_CLOCK_PIOSC);

    //
    // Select the alternate (UART) function for these pins.
    // TODO: change this to select the port/pin you are using.
    //
    GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

    //
    // Initialize the UART for console I/O.
    //
    UARTStdioConfig(0, 115200, 16000000);
}

//*****************************************************************************
//
// Main Test Code...
//
//*****************************************************************************
int
main(void)
{
    //
    // Run from the PLL at 120 MHz.
    //
    g_ui32SysClock = SysCtlClockFreqSet((SYSCTL_XTAL_16MHZ |
                SYSCTL_OSC_INT | SYSCTL_USE_PLL |
                SYSCTL_CFG_VCO_480), 120000000);


	//
	// Initalize UART-0 COM
	//
	InitConsole();
    UARTprintf("UART Is Working...\n");

    //
    // Enable GPIO Module and Configure the Pin Mux.
    //
	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOP);
	while(!(SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOP)));
	GPIOPinConfigure(GPIO_PP3_RTCCLK);
    GPIODirModeSet(GPIO_PORTP_BASE, GPIO_PIN_3, GPIO_DIR_MODE_HW);
    GPIOPadConfigSet(GPIO_PORTP_BASE, GPIO_PIN_3, GPIO_STRENGTH_8MA, GPIO_PIN_TYPE_STD);

	//
	// Enable Hibernate Module Clock and wait for module to be ready
	//
	SysCtlPeripheralEnable(SYSCTL_PERIPH_HIBERNATE);
	while(!(SysCtlPeripheralReady(SYSCTL_PERIPH_HIBERNATE)));

	// Configure Hibernate module clock.
	HibernateEnableExpClk(g_ui32SysClock);

	// Enable RTC mode.
	HibernateRTCEnable();

	// Configure the hibernate module counter to 24-hour calendar mode.
	HibernateCounterMode(HIBERNATE_COUNTER_24HR);


	// Configure HIBCC for RTCOSC available
	HWREG(HIB_CC) = HIB_CC_SYSCLKEN;

	while(1);

}