begriffs open source - cmsis-freertos/blob - CMSIS/RTOS2/FreeRTOS/Source/os

1 /**************************************************************************//**

2 * @file os_systick.c

3 * @brief CMSIS OS Tick SysTick implementation

4 * @version V1.0.0

5 * @date 05. June 2017

6 ******************************************************************************/

7 /*

9 *

10 * SPDX-License-Identifier: Apache-2.0

11 *

12 * Licensed under the Apache License, Version 2.0 (the License); you may

13 * not use this file except in compliance with the License.

14 * You may obtain a copy of the License at

15 *

16 * www.apache.org/licenses/LICENSE-2.0

17 *

18 * Unless required by applicable law or agreed to in writing, software

19 * distributed under the License is distributed on an AS IS BASIS, WITHOUT

20 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

21 * See the License for the specific language governing permissions and

22 * limitations under the License.

23 */

25 #include "os_tick.h"

27 #include "RTE_Components.h"

28 #include CMSIS_device_header

30 #ifdef SysTick

32 #ifndef SYSTICK_IRQ_PRIORITY

33 #define SYSTICK_IRQ_PRIORITY 0xFFU

34 #endif

36 static uint8_t PendST;

38 // Setup OS Tick.

39 __WEAK int32_t OS_Tick_Setup (uint32_t freq, IRQHandler_t handler) {

40 uint32_t load;

41 (void)handler;

43 if (freq == 0U) {

44 return (-1);

45 }

47 load = (SystemCoreClock / freq) - 1U;

48 if (load > 0x00FFFFFFU) {

49 return (-1);

50 }

52 NVIC_SetPriority(SysTick_IRQn, SYSTICK_IRQ_PRIORITY);

54 SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk | SysTick_CTRL_TICKINT_Msk;

55 SysTick->LOAD = load;

56 SysTick->VAL = 0U;

58 PendST = 0U;

60 return (0);

61 }

63 /// Enable OS Tick.

64 __WEAK int32_t OS_Tick_Enable (void) {

66 if (PendST != 0U) {

67 PendST = 0U;

68 SCB->ICSR = SCB_ICSR_PENDSTSET_Msk;

69 }

71 SysTick->CTRL |= SysTick_CTRL_ENABLE_Msk;

73 return (0);

74 }

76 /// Disable OS Tick.

77 __WEAK int32_t OS_Tick_Disable (void) {

79 SysTick->CTRL &= ~SysTick_CTRL_ENABLE_Msk;

81 if ((SCB->ICSR & SCB_ICSR_PENDSTSET_Msk) != 0U) {

82 SCB->ICSR = SCB_ICSR_PENDSTCLR_Msk;

83 PendST = 1U;

84 }

86 return (0);

87 }

89 // Acknowledge OS Tick IRQ.

90 __WEAK int32_t OS_Tick_AcknowledgeIRQ (void) {

91 (void)SysTick->CTRL;

92 return (0);

93 }

95 // Get OS Tick IRQ number.

96 __WEAK int32_t OS_Tick_GetIRQn (void) {

97 return (SysTick_IRQn);

98 }

100 // Get OS Tick clock.

101 __WEAK uint32_t OS_Tick_GetClock (void) {

102 return (SystemCoreClock);

103 }

104

105 // Get OS Tick interval.

106 __WEAK uint32_t OS_Tick_GetInterval (void) {

107 return (SysTick->LOAD + 1U);

108 }

109

110 // Get OS Tick count value.

111 __WEAK uint32_t OS_Tick_GetCount (void) {

112 uint32_t load = SysTick->LOAD;

113 return (load - SysTick->VAL);

114 }

115

116 // Get OS Tick overflow status.

117 __WEAK uint32_t OS_Tick_GetOverflow (void) {

118 return ((SysTick->CTRL >> 16) & 1U);

119 }

120

121 #endif // SysTick