Diff: targets/cmsis/TARGET_ARM_SSG/TARGET_BEETLE/systick_timer.c

Revision:

144:ef7eb2e8f9f7

diff -r 423e1876dc07 -r ef7eb2e8f9f7 targets/cmsis/TARGET_ARM_SSG/TARGET_BEETLE/systick_timer.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/cmsis/TARGET_ARM_SSG/TARGET_BEETLE/systick_timer.c	Fri Sep 02 15:07:44 2016 +0100
@@ -0,0 +1,94 @@
+/*
+ * PackageLicenseDeclared: Apache-2.0
+ * Copyright (c) 2015 ARM Limited
+ *
+ * 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
+ *
+ *     http://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 "cmsis.h"
+#include "systick_timer.h"
+
+volatile uint32_t MyTicks;
+
+/* Private Data SysTick */
+static uint32_t clock;
+
+/*
+ * This Timer is written for MBED OS so the interrupt
+ * is used to keep track of the overflow.
+ */
+#define SYSTICK_MAX_RELOAD    0xFFFFFFFF
+#define SYSTICK_DIVIDER_US    (SystemCoreClock/1000000)
+
+void SysTick_IRQ_Handler(void)
+{
+    MyTicks++;
+#if 0
+    printf("System Tick Interrupt: %u\n\r", MyTicks);
+#endif
+}
+
+/*
+ * SysTick_Initialize(): Initializes the SysTick timer
+ */
+void SysTick_Initialize(void)
+{
+    clock = SYSTICK_MAX_RELOAD;
+#if 0
+    printf("\n\rEnable System Tick Interrupt...\n\r");
+#endif
+    MyTicks=0;
+
+    /* SysTick Reload Value Register */
+    SysTick->LOAD = clock;
+
+    /*
+     * SysTick_CTRL_CLKSOURCE_Msk : Use core's clock
+     * SysTick_CTRL_ENABLE_Msk : Enable SysTick
+     * SysTick_CTRL_TICKINT_Msk : Active the SysTick interrupt on the NVIC
+     */
+    SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk
+        | SysTick_CTRL_ENABLE_Msk
+        | SysTick_CTRL_TICKINT_Msk;
+
+    /* Register the Interrupt */
+    NVIC_SetVector(SysTick_IRQn, (uint32_t)SysTick_IRQ_Handler);
+    NVIC_EnableIRQ(SysTick_IRQn);
+}
+
+/*
+ * SysTick_Disable(): Disables the SysTick timer
+ */
+void SysTick_Disable(void)
+{
+    /* Disable SysTick */
+    SysTick->CTRL = 0;
+}
+
+/*
+ * SysTick_Read(): Read SysTick Value
+ * @return: the SysTick VALUE
+ */
+uint32_t SysTick_Read(void)
+{
+    return ((clock - (SysTick->VAL)) / SYSTICK_DIVIDER_US);
+}
+
+/*
+ * SysTick_Overflow(): Read SysTick Overflow Value
+ * @return: the SysTick Overflow VALUE
+ */
+uint32_t SysTick_Overflow(void)
+{
+    return MyTicks;
+}