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unlock NMI on PF0 but got into FaultISR loop

Gavin Lin1
Expert 1875 points
Other Parts Discussed in Thread: TM4C1231H6PM
Currently, I use TM4C1231H6PM mcu + cc3000 for application.
I use SSI1 as the communication interface between mcu and cc3000.
For this purpose, I have to unlock NMI on GPIO PF0.
I use the sample code to unlock PF0:
#define GPIO_LOCK_KEY_DD        0x4C4F434B
 
        //unlock PF0
HWREG(GPIO_PORTF_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY_DD;
HWREG(GPIO_PORTF_BASE + GPIO_O_CR) |= 0x01;
     HWREG(GPIO_PORTF_BASE + GPIO_O_LOCK) = 0;
 
At the first bootup, it works.
 
But I always get the failed in the following re-boot.
 
I attach JTAG to check the failed point and I find it's always blocked in FaultISR loop.
 
When system runs at 
 
HWREG(GPIO_PORTF_BASE + GPIO_O_CR) |= 0x01;
 
It will jump to FaultISR loop.
 
Anyone meet this issue before?
 
thanks
Gavin

 

  • 0
    Guru 86595 points

    Hi Gavin,

         Verify if there is actually a GPIO_LOCK_KEY_DD at your hw_gpio.h.

         Try without the _DD. See, code below from buttons.c. 

         HWREG(GPIO_PORTF_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;

         HWREG(GPIO_PORTF_BASE + GPIO_O_CR) |= 0x01;

         HWREG(GPIO_PORTF_BASE + GPIO_O_LOCK) = 0;

    -kel

    - post edited

  • 0
    TI__Guru**** 244380 points

    Hello Gavin,

    I would take a step back in the debug. Can you check if the SYSCTL_RCGC_GPIO Register at 0x400FE608 has bit-5 corresponding to Port-F set?

    Regards

    Amit