Hibernation module won't enable clocking on TM4C123

Hello all,

i'm trying to get the hibernation module to work on my tiva launchpad TM4C123. The problem is: 

When I try to enable the hibernation module clock source, the Write Complete/Capable Bit will not be set after trying to access the hibernation control register (HIB_CTL).

This is what my code looks like. I have tried it using the TI Peripheral Library as well as implementing it with the CMSIS driver.

The code using the CMSIS driver:

SystemInit();
		
SYSCTL->RCGCHIB = 0x01; 	// Provide clock to HIB

while((SYSCTL->PRHIB & 0x01) == 0);	// wait for hib module to be accessible
		
while((HIB->CTL & 0x80000000) == 0);  // check if hib interface is ready to accept write

HIB->CTL = 0x40;	// Enable hib module clock source
		
while((HIB->CTL & 0x80000000) == 0);  // <-- infinite while loop

HIB->CTL |= 0x0100;

while((HIB->CTL & 0x80000000) == 0); 

Code using the peripheral library:

SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
                       SYSCTL_XTAL_16MHZ);
	
SysCtlPeripheralEnable(SYSCTL_PERIPH_HIBERNATE);
			
HibernateEnableExpClk(SysCtlClockGet()); // this is where it's stuck in the while loop

HibernateGPIORetentionEnable();

The HibernateEnableExpClk()-Function calls the _HibernateWriteComplete(), which just waits for the HIB_CTL_WRC bit to be set (and does not happen).

While debugging both methods the hibernation control register HIB_CTL is equal to 0x00000000, after setting the CK32EN bit.


Am i missing something in my code or do you have any ideas why the initialization of the hibernation module is not working?


Best regards,
Mike