mbed os with nrf51 internal bandgap enabled to read battery level

Dependents:   BLE_file_test BLE_Blink ExternalEncoder

Revision:
0:f269e3021894
diff -r 000000000000 -r f269e3021894 targets/TARGET_NORDIC/TARGET_NRF5/rtc_api.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NORDIC/TARGET_NRF5/rtc_api.c	Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,92 @@
+/* 
+ * Copyright (c) 2013 Nordic Semiconductor ASA
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ * 
+ *   1. Redistributions of source code must retain the above copyright notice, this list 
+ *      of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form, except as embedded into a Nordic Semiconductor ASA 
+ *      integrated circuit in a product or a software update for such product, must reproduce 
+ *      the above copyright notice, this list of conditions and the following disclaimer in 
+ *      the documentation and/or other materials provided with the distribution.
+ *
+ *   3. Neither the name of Nordic Semiconductor ASA nor the names of its contributors may be 
+ *      used to endorse or promote products derived from this software without specific prior 
+ *      written permission.
+ *
+ *   4. This software, with or without modification, must only be used with a 
+ *      Nordic Semiconductor ASA integrated circuit.
+ *
+ *   5. Any software provided in binary or object form under this license must not be reverse 
+ *      engineered, decompiled, modified and/or disassembled. 
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 
+ */
+
+#include "rtc_api.h"
+
+#if DEVICE_RTC
+
+#include "common_rtc.h"
+#include "nrf_drv_clock.h"
+#include "app_util_platform.h"
+
+static time_t m_time_base;
+
+void rtc_init(void)
+{
+    common_rtc_init();
+}
+
+void rtc_free(void)
+{
+    // A common counter is used for RTC, lp_ticker and us_ticker, so it can't be
+    // disabled here, but this does not cause any extra cost. Besides, currently
+    // this function is not used by RTC API in mbed-drivers.
+}
+
+int rtc_isenabled(void)
+{
+    return m_common_rtc_enabled;
+}
+
+static uint32_t rtc_seconds_get(void)
+{
+    // Convert current counter value to seconds.
+    uint32_t seconds = nrf_rtc_counter_get(COMMON_RTC_INSTANCE) / RTC_INPUT_FREQ;
+    // Add proper amount of seconds for each registered overflow of the counter.
+    uint32_t seconds_per_overflow = (1uL << RTC_COUNTER_BITS) / RTC_INPUT_FREQ;
+    return (seconds + (m_common_rtc_overflows * seconds_per_overflow));
+}
+
+time_t rtc_read(void)
+{
+    return m_time_base + rtc_seconds_get();
+}
+
+void rtc_write(time_t t)
+{
+    uint32_t seconds;
+    do {
+        seconds = rtc_seconds_get();
+        m_time_base = t - seconds;
+    // If the number of seconds indicated by the counter changed during the
+    // update of the time base, just repeat the update, now using the new
+    // number of seconds.
+    } while (seconds != rtc_seconds_get());
+}
+
+#endif // DEVICE_RTC