ARM Cortex M4 TIVAC 

Port initialization F 

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In this post, we share the Code to initialize the F port of the ARM Cortex M4 TivaC123GH6PMI.

The first part is the define block which shows the address of each register such as GIPO-DATA.

The second one shows the function of initialization of the F port. Where the Switc1 and Switch 2 of the card are inputs, and the PF3 bit is an output connected to the green LED of the card.

Any questions you can ask on this blog.

For more information here we share a reference [1].

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#define GPIO_PORTF_DATA_R   (*((volatile unsigned long *)0x400253FC))

#define GPIO_PORTF_DIR_R        (*((volatile unsigned long *)0x40025400))

#define GPIO_PORTF_AFSEL_R      (*((volatile unsigned long *)0x40025420))

#define GPIO_PORTF_PUR_R        (*((volatile unsigned long *)0x40025510))

#define GPIO_PORTF_DEN_R        (*((volatile unsigned long *)0x4002551C))

#define GPIO_PORTF_LOCK_R       (*((volatile unsigned long *)0x40025520))

#define GPIO_PORTF_CR_R         (*((volatile unsigned long *)0x40025524))

#define GPIO_PORTF_AMSEL_R      (*((volatile unsigned long *)0x40025528))

#define GPIO_PORTF_PCTL_R       (*((volatile unsigned long *)0x4002552C))

#define SYSCTL_RCGC2_R          (*((volatile unsigned long *)0x400FE108))

void PortF_Init(void){ volatile unsigned long delay;

  SYSCTL_RCGC2_R |= 0x00000020;    // 1) F clock

  delay = SYSCTL_RCGC2_R;          // delay   

  GPIO_PORTF_LOCK_R = 0x4C4F434B;  // 2) unlock PortF PF0  

  GPIO_PORTF_CR_R |= 0x1F;          // allow changes to PF4-0       

  GPIO_PORTF_AMSEL_R &= 0x00;       // 3) disable analog function

  GPIO_PORTF_PCTL_R &= 0x00000000;  // 4) GPIO clear bit PCTL  

  GPIO_PORTF_DIR_R &= ~0x11;        // 5.1) PF4,PF0 input, 

  GPIO_PORTF_DIR_R |= 0x08;         // 5.2) PF3 output  

  GPIO_PORTF_AFSEL_R &= 0x00;       // 6) no alternate function

  GPIO_PORTF_PUR_R |= 0x11; //enable pullup resistors on PF4,PF0       

  GPIO_PORTF_DEN_R |= 0x1F;  // 7) enable digital pins PF4-PF0       

}

[1] Jonathan Valvano, Embedded Systems: Introduction to ARM Cortex-M Microcontrollers