UNLOCKING NMI PIN PF0

Hi,

Your code contradicts your intent: you would like it to be PF0, but modify PORTD - a clean code could look like this:

// Unlock PF0 so we can change it to a GPIO input
// Once we have enabled (unlocked) the commit register then re-lock it
// to prevent further changes.
//
HWREG(BUTTONS_GPIO_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
HWREG(BUTTONS_GPIO_BASE + GPIO_O_CR) |= 0x01;
HWREG(BUTTONS_GPIO_BASE + GPIO_O_LOCK) = 0;

Petrei

Hi,

its giving error if i use "BUTTONS_GPIO_BASE" 

Hi 

am trying this to make PFO as GPIO pin

HWREG(GPIO_PORTF_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
HWREG(GPIO_PORTF_BASE + GPIO_O_CR) |= 0x01;
HWREG(GPIO_PORTF_BASE + GPIO_O_AFSEL) |= 0x000;
HWREG(GPIO_PORTF_BASE + GPIO_O_LOCK) = 0;

is this correct steps to unlock PFO NMI pin

Hi,

My code was an excerpt from ButtonsInit() function - (this is why is in blue) so yes, is OK to replace with GPIO_PORF_BASE. But  your third line involving AFSEL is useless - you must remove it.

Petrei

hi,

i removed that  alternate function enable line... and am making PFO low but it is still high...

unlock code is follwed by this code

ROM_GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE,GPIO_PIN_0);
// ROM_GPIOPadConfigSet(GPIO_PORTF_BASE, GPIO_PIN_0,GPIO_STRENGTH_8MA, GPIO_PIN_TYPE_STD_WPD);
GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,0x00);

hi,

i want to make PF0 pin low, since it NMI pin first i unlocked it and then making it as an out pin and writing 0 to it.Is this the correct way.i followed the unlocking procedure what you given but still the pin is high.can you please help me out of this.. 

Hi,

Insert these two lines before locking again:

Petrei said:

your third line involving AFSEL is useless

Really?   As poster seeks to use PF0 as GPIO - and as AFSEL is required to be clear (0) to so serve - might you reconsider?

To clear the bit, the line would need to be written as:

HWREG(GPIO_PORTF_BASE + GPIO_O_AFSEL) &= ~0x001;

--Bobby

@cb1,

My mistake - I was thinking the poster would call GPIODirModeSet which manage AFSEL...

Petrei

@ friend Petrei,

Did not consider that a "mistake" - reacted to, "useless."  (it was not)

But do note - "GPIODirModeSet()" has been encapsulated (swallowed) w/in, "GPIOPinType()" - thus may be excess to many/most needs... (gpio.c reveals - for those who may care...)

In all these configs how can i really put my PF ports as a SSI1 module? Any configuration diferent from enabling it as a digital GPIO I/O?

Hi,

If any time you have problems, you may use PinMux utility. Here it is what is generated quickly:

void
PortFunctionInit(void)
{
    //
    // Enable Peripheral Clocks 
    //
    MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI1);
    MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);

    //
    // Enable pin PF2 for SSI1 SSI1CLK
    //
    MAP_GPIOPinConfigure(GPIO_PF2_SSI1CLK);
    MAP_GPIOPinTypeSSI(GPIO_PORTF_BASE, GPIO_PIN_2);

    //
    // Enable pin PF0 for SSI1 SSI1RX
    // First open the lock and select the bits we want to modify in the GPIO commit register.
    //
    HWREG(GPIO_PORTF_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;
    HWREG(GPIO_PORTF_BASE + GPIO_O_CR) = 0x1;

    //
    // Now modify the configuration of the pins that we unlocked.
    //
    MAP_GPIOPinConfigure(GPIO_PF0_SSI1RX);
    MAP_GPIOPinTypeSSI(GPIO_PORTF_BASE, GPIO_PIN_0);

    //
    // Enable pin PF1 for SSI1 SSI1TX
    //
    MAP_GPIOPinConfigure(GPIO_PF1_SSI1TX);
    MAP_GPIOPinTypeSSI(GPIO_PORTF_BASE, GPIO_PIN_1);

    //
    // Enable pin PF3 for SSI1 SSI1FSS
    //
    MAP_GPIOPinConfigure(GPIO_PF3_SSI1FSS);
    MAP_GPIOPinTypeSSI(GPIO_PORTF_BASE, GPIO_PIN_3);
} 

Petrei