Stellaris LaunchPad LM4F120 - PUR config problem

Alessandro Mendes

Prodigy 100 points

Hi all,

A am trying configure pullups in the PF0 and PF4 to works with de buttons installed in the Stellaris LauchPad.

Only pullup in PF4 works, the value of PUR register don't change to PF0.

This can be a GPIO_BLOCK problem?

I tried change the value of this register without sucess.

Anyone know about this?

My code:

ROM_SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
SYSCTL_XTAL_16MHZ);

ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

ROM_GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_1);
ROM_GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_2);
ROM_GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_3);
ROM_GPIODirModeSet(GPIO_PORTF_BASE, GPIO_PIN_4, GPIO_DIR_MODE_IN); // SW1 and Sw2 as Input
ROM_GPIODirModeSet(GPIO_PORTF_BASE, GPIO_PIN_0, GPIO_DIR_MODE_IN);

GPIO_PORTF_DEN_R |= GPIO_PIN_4;
GPIO_PORTF_DEN_R |= GPIO_PIN_0; // This is a Digita Inputs
GPIO_PORTF_PUR_R |= GPIO_PIN_4; // Pullups on S1 and S2 (HERE WORK)
GPIO_PORTF_PUR_R |= GPIO_PIN_0; //(HERE DON'T WORK)

Thanks,

Alessandro

over 13 years ago

0 cb1_mobile over 13 years ago

Guru 117855 points

PF0 is an NMI pin on the LM4F Series! As such - it requires, "special unlocking" to re-purpose.

(you are not alone in missing this - about my 10th response to users falling into this same trap...)

If I were you - I'd avoid PF0 for the interim - use another pin from Port F...

0 Alessandro Mendes over 13 years ago in reply to cb1_mobile

Prodigy 100 points

Hi cb1_mobile,

Thanks for your response.

I was soldering a resistor as pullup and I tried other code below and now works:

ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);
HWREG(BUTTONS_GPIO_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY_DD;
HWREG(BUTTONS_GPIO_BASE + GPIO_O_CR) |= 0x01;
HWREG(BUTTONS_GPIO_BASE + GPIO_O_LOCK) = 0;

Thanks again,

Alessandro

0 cb1_mobile over 13 years ago in reply to Alessandro Mendes

Guru 117855 points

Alessandro - Glad - good for you - happy to assist - "Unlock" was indeed the Solution...

Might you issue a valued, Verified Answer upon my post as well - which correctly (and quickly - 4 min!) identified your issue?

0 Alessandro Mendes over 13 years ago in reply to cb1_mobile

Prodigy 100 points

ok cb1_mobile, no probrem, I did the Verifiy Answer.

Tks,

Alessandro

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Stellaris LaunchPad LM4F120 - PUR config problem