Tiva sw1 int source

sw1_int.c

1. /* sw1_int.c

2.  *

3.  * Runs on EK-TM4C123GXL LaunchPad

4.  *

5.  * GPIO PORTF interrupt that will toggle the on board Blue LED

6.  * on rising edge whenever a user switch (SW1) is pressed.

7.  *

8.  */

9. #include <stdint.h>

10. #include "inc/tm4c123gh6pm.h"

12. void DisableInterrupts(void);

13. void EnableInterrupts(void);

14. void WaitForInterrupt(void);

15. void GPIOPortF_Init(void);

16. void GPIOPortF_Handler(void);

18. void GPIOPortF_Init(void)

19. {

21.     SYSCTL_RCGC2_R |= 0x00000020;   /* 1) activate clock for Port F */

23.     GPIO_PORTF_LOCK_R = 0x4C4F434B; /* 2) unlock GPIO Port F */

24.     GPIO_PORTF_CR_R = 0x1F;         /* allow changes to PF4-0 */

25.     GPIO_PORTF_AMSEL_R = 0x00;      /* 3) disable analog on PF */

26.     GPIO_PORTF_PCTL_R = 0x00000000; /* 4) PCTL GPIO on PF4-0 */

27.     GPIO_PORTF_DIR_R = 0x0E;        /* 5) PF4,PF0 in, PF3-1 out */

28.     GPIO_PORTF_AFSEL_R = 0x00;      /* 6) disable alt funct on PF7-0 */

29.     GPIO_PORTF_PUR_R = 0x11;        /* enable pull-up on PF0 and PF4 */

30.     GPIO_PORTF_DEN_R = 0x1F;        /* 7) enable digital I/O on PF4-0 */

32.     GPIO_PORTF_IS_R &= ~0x10;       /*  PF4 is edge-sensitive */

33.     GPIO_PORTF_IBE_R &= ~0x10;      /*  PF4 is not both edges */

34.     GPIO_PORTF_IEV_R &= ~0x10;      /*  PF4 falling edge event */

35.     GPIO_PORTF_ICR_R = 0x10;        /*  Clear flag4 */

36.     GPIO_PORTF_IM_R |= 0x10;        /*  arm interrupt on PF4 */

37.     NVIC_PRI7_R = (NVIC_PRI7_R & 0xFF1FFFFF) | 0x00A00000; /*  priority 5 */

38.     NVIC_EN0_R = 0x40000000;        /*  Enable interrupt 30 in NVIC */

40.     EnableInterrupts();             /* Enable global Interrupt flag (I) */

41. }

43. void GPIOPortF_Handler(void)

44. {

45.     volatile int readback;

47.     GPIO_PORTF_ICR_R = 0x10;        /* clear PF4 int */

48.     GPIO_PORTF_DATA_R ^= (1<<2);    /* toggle Blue LED */

49.     readback = GPIO_PORTF_ICR_R;    /* a read to force clearing of interrupt flag */

50.     readback = readback;

51. }

53. int main(void)

54. {

55.     GPIOPortF_Init();               /* initialize GPIO Port F interrupt */

57.     while(1) {

58.         WaitForInterrupt();

59.     }

60. }

62. /*********** DisableInterrupts ***************

63. *

64. * disable interrupts

65. *

66. * inputs:  none

67. * outputs: none

68. */

70. void DisableInterrupts(void)

71. {

72.     __asm ("    CPSID  I\n");

73. }

75. /*********** EnableInterrupts ***************

76. *

77. * emable interrupts

78. *

79. * inputs:  none

80. * outputs: none

81. */

83. void EnableInterrupts(void)

84. {

85.     __asm  ("    CPSIE  I\n");

86. }

88. /*********** WaitForInterrupt ************************

89. *

90. * go to low power mode while waiting for the next interrupt

91. *

92. * inputs:  none

93. * outputs: none

94. */

96. void WaitForInterrupt(void)

97. {

98.     __asm  ("    WFI\n");

99. }