Diff: targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/rtc_api.c

Revision:

525:c320967f86b9

Child:

526:7c4bdfe6a168

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/rtc_api.c	Tue Apr 28 11:45:12 2015 +0100
@@ -0,0 +1,147 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 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 "device.h"
+#if DEVICE_RTC
+
+#include "rtc_api.h"
+#include "rtc_api_HAL.h"
+#include "em_cmu.h"
+#include "em_rtc.h"
+#include "sleep_api.h"
+
+static bool rtc_inited = false;
+static time_t time_base = 0;
+static uint32_t useflags = 0;
+
+static void (*comp0_handler)(void) = NULL; 
+
+#define RTC_LEAST_ACTIVE_SLEEPMODE EM2
+
+
+void RTC_IRQHandler(void)
+{
+    uint32_t flags;
+    flags = RTC_IntGet();
+    if (flags & RTC_IF_OF)
+    {
+        RTC_IntClear(RTC_IF_OF);
+        /* RTC has overflowed (24 bits). Use time_base as software counter for upper 8 bits. */
+        time_base += 1 << 24;
+    }
+    if (flags & RTC_IF_COMP0)
+    {
+        RTC_IntClear(RTC_IF_COMP0);
+        if (comp0_handler != NULL)
+        {
+            comp0_handler();
+        }
+    }
+}
+
+void rtc_set_comp0_handler(uint32_t handler)
+{
+    comp0_handler = (void (*)(void)) handler;
+}
+
+void rtc_init(void) 
+{
+    /* Register that the RTC is used for timekeeping. */
+    rtc_init_real(RTC_INIT_RTC);
+}
+
+
+void rtc_init_real(uint32_t flags)
+{
+    useflags |= flags;
+
+    if (!rtc_inited)
+    {
+        /* Start LFXO and wait until it is stable */
+        CMU_OscillatorEnable(cmuOsc_LFXO, true, true);
+
+        /* Route the LFXO clock to the RTC */
+        CMU_ClockSelectSet(cmuClock_LFA, LOW_ENERGY_CLOCK_SOURCE);
+        CMU_ClockEnable(cmuClock_RTC, true);
+
+        /* Enable clock to the interface of the low energy modules */
+        CMU_ClockEnable(cmuClock_CORELE, true);
+
+        /* Scale clock to save power */
+        CMU_ClockDivSet(cmuClock_RTC, RTC_CLOCKDIV);
+
+        /* Initialize RTC */
+        RTC_Init_TypeDef init = RTC_INIT_DEFAULT;
+        init.enable = 1;
+        /* Don't use compare register 0 as top value */
+        init.comp0Top = 0;
+
+        /* Enable Interrupt from RTC */
+        RTC_IntEnable(RTC_IEN_OF);
+        NVIC_EnableIRQ(RTC_IRQn);
+        NVIC_SetVector(RTC_IRQn, (uint32_t)RTC_IRQHandler);
+
+        /* Initialize */
+        RTC_Init(&init);
+
+        blockSleepMode(RTC_LEAST_ACTIVE_SLEEPMODE);
+        rtc_inited = true;
+    }
+}
+
+void rtc_free(void) 
+{
+    rtc_free_real(RTC_INIT_RTC);
+}
+
+void rtc_free_real(uint32_t flags)
+{
+    /* Clear use flag */
+    flags &= ~flags; 
+
+    /* Disable the RTC if it was inited and is no longer in use by anyone. */
+    if (rtc_inited && (flags == 0))
+    {
+        NVIC_DisableIRQ(RTC_IRQn);
+        RTC_Reset();
+        CMU_ClockEnable(cmuClock_RTC, false);
+        unblockSleepMode(RTC_LEAST_ACTIVE_SLEEPMODE);
+        rtc_inited = false;
+    }
+}
+
+int rtc_isenabled(void)
+{
+    return rtc_inited;
+}
+
+time_t rtc_read(void)
+{
+    return (time_t) ((RTC_CounterGet() + time_base) >> RTC_FREQ_SHIFT);
+}
+
+void rtc_write(time_t t)
+{
+    /* We have to check that the RTC did not tick while doing this. */
+    /* If the RTC ticks we just redo this. */
+    uint32_t rtc_count;
+    do {
+        rtc_count = RTC_CounterGet();
+        time_base = (t << RTC_FREQ_SHIFT) - rtc_count;
+    } while (rtc_count != RTC_CounterGet());
+}
+
+#endif