Diff: targets/TARGET_Silicon_Labs/TARGET_EFM32/burtc.c

Revision:

186:707f6e361f3e

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_Silicon_Labs/TARGET_EFM32/burtc.c	Fri Jun 22 16:45:37 2018 +0100
@@ -0,0 +1,106 @@
+/***************************************************************************//**
+ * @file rtc_burtc.c
+ *******************************************************************************
+ * @section License
+ * <b>(C) Copyright 2018 Silicon Labs, http://www.silabs.com</b>
+ *******************************************************************************
+ *
+ * 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
+ *
+ * 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
+
+/* Use BURTC on devices that have it, and don't use the RTCC abstraction */
+#if defined(BURTC_PRESENT) && !defined(RTCC_PRESENT)
+
+#include "clocking.h"
+#include "em_cmu.h"
+#include "em_emu.h"
+#include "em_burtc.h"
+#include "rtc_api.h"
+
+void rtc_init(void)
+{
+    /* Only reset & configure the RTC if it has never run before */
+    if(BUS_RegBitRead(&BURTC->CTRL, _BURTC_CTRL_RSTEN_SHIFT)) {
+        EMU_EM4Init_TypeDef em4_init = EMU_EM4INIT_DEFAULT;
+#if (LOW_ENERGY_CLOCK_SOURCE == LFXO)
+        em4_init.osc = emuEM4Osc_LFXO;
+#elif (LOW_ENERGY_CLOCK_SOURCE == LFRCO)
+        em4_init.osc = emuEM4Osc_LFRCO;
+#else
+#error "Can't use BURTC on mbed with ULFRCO"
+#endif
+        EMU_EM4Init(&em4_init);
+
+        BURTC_Init_TypeDef burtc_init = BURTC_INIT_DEFAULT;
+        burtc_init.mode = burtcModeEM4;
+#if (LOW_ENERGY_CLOCK_SOURCE == LFXO)
+        burtc_init.clkSel = burtcClkSelLFXO;
+#elif (LOW_ENERGY_CLOCK_SOURCE == LFRCO)
+        burtc_init.clkSel = burtcClkSelLFRCO;
+#else
+#error "Can't use BURTC on mbed with ULFRCO"
+#endif
+        burtc_init.clkDiv = burtcClkDiv_128;
+        burtc_init.lowPowerMode = burtcLPEnable;
+
+        BURTC_Reset();
+        BUS_RegBitWrite(&RMU->CTRL, _RMU_CTRL_BURSTEN_SHIFT, 0);
+        BURTC_Init(&burtc_init);
+        BURTC_RetRegSet(0, 0);
+        BURTC_RetRegSet(1, 0);
+    }
+}
+
+void rtc_free(void)
+{
+    /* Nothing to release here */
+}
+
+int rtc_isenabled(void)
+{
+    return (BUS_RegBitRead(&BURTC->CTRL, _BURTC_CTRL_RSTEN_SHIFT) == 0);
+}
+
+time_t rtc_read(void)
+{
+    uint32_t ts = 0;
+    uint32_t ts2 = 1;
+    do {
+        if (BURTC->IF & BURTC_IF_OF) {
+            BURTC_RetRegSet(1, BURTC_RetRegGet(1)+1);
+            BURTC->IFC = BURTC_IFC_OF;
+        }
+
+        ts = ts2;
+        ts2 = (BURTC_CounterGet() >> 8) + BURTC_RetRegGet(0) + (BURTC_RetRegGet(1) << 16);
+    } while (ts != ts2);
+    return ts2;
+}
+
+void rtc_write(time_t t)
+{
+    BURTC_RetRegSet(0, t - (BURTC_CounterGet() >> 8));
+    BURTC_RetRegSet(1, 0);
+    if (BURTC->IF & BURTC_IF_OF) {
+        BURTC->IFC = BURTC_IFC_OF;
+    }
+}
+
+#endif /* BURTC_PRESENT && !RTCC_PRESENT */
+#endif /* DEVICE_RTC */
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