1. I am make PF0 & PF4 as input pull up.
2. But as soon as I am trying to access GPIO->DIR register, I get hardfault.
3. I have read that this occur if clock is not enabled for GPIO port. But I have enable clock also.
4. I am using launchpad & MCU TM4C123GH6PM .
5. Code snippet is below. I am using keil V4
Code
#define REG32_BIT_3 ((uint32_t)0x00000008)
#define REG32_BIT_4 ((uint32_t)0x00000010)
#define REG32_BIT_5 ((uint32_t)0x00000020)
#define REG32_BIT_16 ((uint32_t)0x00010000)
#define REG32_BIT_17 ((uint32_t)0x00020000)
#define REG32_BIT_18 ((uint32_t)0x00040000)
#define REG32_BIT_19 ((uint32_t)0x00080000)
/* PF4 as input pull up */
SYSCTL->RCGCGPIO |= REG32_BIT_5; /* enable PORTF clock */
__NOP();
__NOP();
__NOP();
__NOP();
__NOP(); /* 5 NOPs */
GPIOF_AHB->DIR &= (u32_t)(~REG32_BIT_4); /* make as input */
GPIOF_AHB->AFSEL &= (u32_t)(~REG32_BIT_4); /* used as GPIO */
GPIOF_AHB->PUR |= REG32_BIT_4; /* pull up enabled */
GPIOF_AHB->PDR &= (u32_t)(~REG32_BIT_4); /* pull down disabled */
GPIOF_AHB->ODR &= (u32_t)(~REG32_BIT_4); /* not open drain */
GPIOF_AHB->AMSEL &= (u32_t)(~REG32_BIT_4); /* analog function disabled */
GPIOF_AHB->PCTL &= (u32_t)( ~(REG32_BIT_16 | REG32_BIT_17 | REG32_BIT_18 | REG32_BIT_19) ); /* GPIO */
GPIOF_AHB->DEN |= REG32_BIT_4; /* digital function enabled */
/* PF0 as input pull up */
SYSCTL->RCGCGPIO |= REG32_BIT_5; /* enable PORTF clock */
__NOP();
__NOP();
__NOP();
__NOP();
__NOP(); /* 5 NOPs */
GPIOF_AHB->LOCK = 0x4c4f434bU; /* write lock key */
GPIOF_AHB->CR |= REG32_BIT_0; /* enable write to PF0 pin */
GPIOF_AHB->DIR &= (u32_t)(~REG32_BIT_0); /* make as input */
GPIOF_AHB->AFSEL &= (u32_t)(~REG32_BIT_0); /* used as GPIO */
GPIOF_AHB->PUR |= REG32_BIT_0; /* pull up enabled */
GPIOF_AHB->PDR &= (u32_t)(~REG32_BIT_0); /* pull down disabled */
GPIOF_AHB->ODR &= (u32_t)(~REG32_BIT_0); /* not open drain */
GPIOF_AHB->AMSEL &= (u32_t)(~REG32_BIT_0); /* analog function disabled */
GPIOF_AHB->PCTL &= (u32_t)( ~(REG32_BIT_0 | REG32_BIT_1 | REG32_BIT_2 | REG32_BIT_3) ); /* GPIO */
GPIOF_AHB->DEN |= REG32_BIT_0; /* digital function enabled */
