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os_systick.c

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+/**************************************************************************//**
+ * @file     os_systick.c
+ * @brief    CMSIS OS Tick SysTick implementation
+ * @version  V1.0.1
+ * @date     29. November 2017
+ ******************************************************************************/
+/*
+ * Copyright (c) 2017-2017 Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <rtthread.h>
+#include "os_tick.h"
+#include "board.h"
+
+#ifdef  SysTick
+
+#ifndef SYSTICK_IRQ_PRIORITY
+#define SYSTICK_IRQ_PRIORITY    0xFFU
+#endif
+
+static uint8_t PendST;
+
+// Setup OS Tick.
+RT_WEAK int32_t OS_Tick_Setup (uint32_t freq, IRQHandler_t handler) {
+  uint32_t load;
+  (void)handler;
+
+  if (freq == 0U) {
+    return (-1);
+  }
+
+  load = (SystemCoreClock / freq) - 1U;
+  if (load > 0x00FFFFFFU) {
+    return (-1);
+  }
+
+  NVIC_SetPriority(SysTick_IRQn, SYSTICK_IRQ_PRIORITY);
+
+  SysTick->CTRL =  SysTick_CTRL_CLKSOURCE_Msk | SysTick_CTRL_TICKINT_Msk;
+  SysTick->LOAD =  load;
+  SysTick->VAL  =  0U;
+
+  PendST = 0U;
+
+  return (0);
+}
+
+/// Enable OS Tick.
+RT_WEAK void OS_Tick_Enable (void) {
+
+  if (PendST != 0U) {
+    PendST = 0U;
+    SCB->ICSR = SCB_ICSR_PENDSTSET_Msk;
+  }
+
+  SysTick->CTRL |=  SysTick_CTRL_ENABLE_Msk;
+}
+
+/// Disable OS Tick.
+RT_WEAK void OS_Tick_Disable (void) {
+
+  SysTick->CTRL &= ~SysTick_CTRL_ENABLE_Msk;
+
+  if ((SCB->ICSR & SCB_ICSR_PENDSTSET_Msk) != 0U) {
+    SCB->ICSR = SCB_ICSR_PENDSTCLR_Msk;
+    PendST = 1U;
+  }
+}
+
+// Acknowledge OS Tick IRQ.
+RT_WEAK void OS_Tick_AcknowledgeIRQ (void) {
+  (void)SysTick->CTRL;
+}
+
+// Get OS Tick IRQ number.
+RT_WEAK int32_t  OS_Tick_GetIRQn (void) {
+  return ((int32_t)SysTick_IRQn);
+}
+
+// Get OS Tick clock.
+RT_WEAK uint32_t OS_Tick_GetClock (void) {
+  return (SystemCoreClock);
+}
+
+// Get OS Tick interval.
+RT_WEAK uint32_t OS_Tick_GetInterval (void) {
+  return (SysTick->LOAD + 1U);
+}
+
+// Get OS Tick count value.
+RT_WEAK uint32_t OS_Tick_GetCount (void) {
+  uint32_t load = SysTick->LOAD;
+  return  (load - SysTick->VAL);
+}
+
+// Get OS Tick overflow status.
+RT_WEAK uint32_t OS_Tick_GetOverflow (void) {
+  return ((SysTick->CTRL >> 16) & 1U);
+}
+
+#endif  // SysTick