Diff: targets/TARGET_STM/us_ticker_16b.c

Revision:

0:098463de4c5d

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_STM/us_ticker_16b.c	Wed Jan 25 20:34:15 2017 +0000
@@ -0,0 +1,129 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2016 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 <stddef.h>
+#include "us_ticker_api.h"
+#include "PeripheralNames.h"
+#include "hal_tick.h"
+
+// A 16-bit timer is used
+#if TIM_MST_16BIT
+
+TIM_HandleTypeDef TimMasterHandle;
+
+volatile uint32_t SlaveCounter = 0;
+volatile uint32_t oc_int_part = 0;
+volatile uint16_t oc_rem_part = 0;
+volatile uint8_t tim_it_update; // TIM_IT_UPDATE event flag set in timer_irq_handler()
+volatile uint32_t tim_it_counter = 0; // Time stamp to be updated by timer_irq_handler()
+
+static int us_ticker_inited = 0;
+
+void set_compare(uint16_t count)
+{
+    TimMasterHandle.Instance = TIM_MST;
+    // Set new output compare value
+    __HAL_TIM_SetCompare(&TimMasterHandle, TIM_CHANNEL_1, count);
+    // Enable IT
+    __HAL_TIM_ENABLE_IT(&TimMasterHandle, TIM_IT_CC1);
+}
+
+void us_ticker_init(void)
+{
+    if (us_ticker_inited) return;
+    us_ticker_inited = 1;
+
+    TimMasterHandle.Instance = TIM_MST;
+
+    HAL_InitTick(0); // The passed value is not used
+}
+
+uint32_t us_ticker_read()
+{
+    uint32_t counter;
+
+    TimMasterHandle.Instance = TIM_MST;
+
+    if (!us_ticker_inited) us_ticker_init();
+
+#if defined(TARGET_STM32L0)
+    uint16_t cntH_old, cntH, cntL;
+    do {
+        // For some reason on L0xx series we need to read and clear the
+        // overflow flag which give extra time to propelry handle possible
+        // hiccup after ~60s
+        if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_CC1OF) == SET) {
+            __HAL_TIM_CLEAR_FLAG(&TimMasterHandle, TIM_FLAG_CC1OF);
+        }
+        cntH_old = SlaveCounter;
+        if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_UPDATE) == SET) {
+            cntH_old += 1;
+        }
+        cntL = TIM_MST->CNT;
+        cntH = SlaveCounter;
+        if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_UPDATE) == SET) {
+            cntH += 1;
+        }
+    } while(cntH_old != cntH);
+    // Glue the upper and lower part together to get a 32 bit timer
+    return (uint32_t)(cntH << 16 | cntL);
+#else
+    tim_it_update = 0; // Clear TIM_IT_UPDATE event flag
+    counter = TIM_MST->CNT + (uint32_t)(SlaveCounter << 16); // Calculate new time stamp
+    if (tim_it_update == 1) {
+        return tim_it_counter; // In case of TIM_IT_UPDATE return the time stamp that was calculated in timer_irq_handler()
+    }
+    else {
+        return counter; // Otherwise return the time stamp calculated here
+    }
+#endif
+}
+
+void us_ticker_set_interrupt(timestamp_t timestamp)
+{
+    int delta = (int)((uint32_t)timestamp - us_ticker_read());
+
+    uint16_t cval = TIM_MST->CNT;
+
+    if (delta <= 0) { // This event was in the past
+        us_ticker_irq_handler();
+    } else {
+        oc_int_part = (uint32_t)(delta >> 16);
+        oc_rem_part = (uint16_t)(delta & 0xFFFF);
+        if (oc_rem_part <= (0xFFFF - cval)) {
+            set_compare(cval + oc_rem_part);
+            oc_rem_part = 0;
+        } else {
+            set_compare(0xFFFF);
+            oc_rem_part = oc_rem_part - (0xFFFF - cval);
+        }
+    }
+}
+
+void us_ticker_disable_interrupt(void)
+{
+    TimMasterHandle.Instance = TIM_MST;
+    __HAL_TIM_DISABLE_IT(&TimMasterHandle, TIM_IT_CC1);
+}
+
+void us_ticker_clear_interrupt(void)
+{
+    TimMasterHandle.Instance = TIM_MST;
+    if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_CC1) == SET) {
+        __HAL_TIM_CLEAR_FLAG(&TimMasterHandle, TIM_FLAG_CC1);
+    }
+}
+
+#endif // TIM_MST_16BIT