STM32L0 - Add low power timer

Author: svastm

hal/targets/hal/TARGET_STM/TARGET_STM32L0/lp_ticker.c

@@ -0,0 +1,83 @@
+/* mbed Microcontroller Library
+ *******************************************************************************
+ * Copyright (c) 2016, STMicroelectronics
+ * 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 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 STMicroelectronics nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * 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 "device.h"
+
+#if DEVICE_LOWPOWERTIMER
+
+#include "ticker_api.h"
+#include "lp_ticker_api.h"
+#include "rtc_api.h"
+#include "rtc_api_hal.h"
+
+static uint8_t lp_ticker_inited = 0;
+
+void lp_ticker_init(void)
+{
+    if (lp_ticker_inited) return;
+    lp_ticker_inited = 1;
+    
+    rtc_init();
+    rtc_set_irq_handler((uint32_t) lp_ticker_irq_handler);
+}
+
+uint32_t lp_ticker_read(void)
+{
+    uint32_t usecs;
+    time_t time;
+
+    lp_ticker_init();
+    
+    do {
+      time = rtc_read();
+      usecs = rtc_read_subseconds();
+    } while (time != rtc_read());
+    
+    return (time * 1000000) + usecs;
+}
+
+void lp_ticker_set_interrupt(timestamp_t timestamp)
+{
+    uint32_t delta;
+
+    delta = timestamp - lp_ticker_read();
+    rtc_set_wake_up_timer(delta);
+}
+
+void lp_ticker_disable_interrupt(void)
+{
+    rtc_deactivate_wake_up_timer();
+}
+
+void lp_ticker_clear_interrupt(void)
+{
+    
+}
+
+#endif

hal/targets/hal/TARGET_STM/TARGET_STM32L0/rtc_api.c

@@ -1,6 +1,6 @@
 /* mbed Microcontroller Library
  *******************************************************************************
- * Copyright (c) 2014, STMicroelectronics
+ * Copyright (c) 2016, STMicroelectronics
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -28,6 +28,7 @@
  *******************************************************************************
  */
 #include "rtc_api.h"
+#include "rtc_api_hal.h"
 
 #if DEVICE_RTC
 
@@ -39,11 +40,29 @@ static int rtc_inited = 0;
 
 static RTC_HandleTypeDef RtcHandle;
 
+#if DEVICE_RTC_LSI
+    #define RTC_CLOCK LSI_VALUE
+#else
+    #define RTC_CLOCK LSE_VALUE
+#endif
+
+#if DEVICE_LOWPOWERTIMER
+    #define RTC_ASYNCH_PREDIV ((RTC_CLOCK - 1) / 0x8000)
+    #define RTC_SYNCH_PREDIV  (RTC_CLOCK / (RTC_ASYNCH_PREDIV + 1) - 1)
+#else
+    #define RTC_ASYNCH_PREDIV (0x007F)
+    #define RTC_SYNCH_PREDIV  (RTC_CLOCK / (RTC_ASYNCH_PREDIV + 1) - 1)    
+#endif
+
+#if DEVICE_LOWPOWERTIMER
+    static void (*irq_handler)(void);
+    static void RTC_IRQHandler(void);
+#endif
+
 void rtc_init(void)
 {
     RCC_OscInitTypeDef RCC_OscInitStruct;
     RCC_PeriphCLKInitTypeDef PeriphClkInitStruct;
-    uint32_t rtc_freq = 0;
 
 #if DEVICE_RTC_LSI
     if (rtc_inited) return;
@@ -74,7 +93,6 @@ void rtc_init(void)
     if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK) {
         error("Cannot initialize RTC with LSI\n");
     }
-    rtc_freq = LSE_VALUE;
 #else
     // Reset Backup domain
     __HAL_RCC_BACKUPRESET_FORCE();
@@ -94,23 +112,35 @@ void rtc_init(void)
     if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK) {
         error("Cannot initialize RTC with LSI\n");
     }
-    // This value is LSI typical value. To be measured precisely using a timer input capture for example.
-    rtc_freq = 38000;
 #endif
 
     // Enable RTC
     __HAL_RCC_RTC_ENABLE();
 
     RtcHandle.Init.HourFormat     = RTC_HOURFORMAT_24;
-    RtcHandle.Init.AsynchPrediv   = 127;
-    RtcHandle.Init.SynchPrediv    = (rtc_freq / 128) - 1;
+    RtcHandle.Init.AsynchPrediv   = RTC_ASYNCH_PREDIV;
+    RtcHandle.Init.SynchPrediv    = RTC_SYNCH_PREDIV;
     RtcHandle.Init.OutPut         = RTC_OUTPUT_DISABLE;
     RtcHandle.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
     RtcHandle.Init.OutPutType     = RTC_OUTPUT_TYPE_OPENDRAIN;
 
     if (HAL_RTC_Init(&RtcHandle) != HAL_OK) {
         error("RTC error: RTC initialization failed.");
     }
+
+#if DEVICE_LOWPOWERTIMER
+#if DEVICE_RTC_LSI
+    rtc_write(0);
+#else
+    if (!rtc_isenabled()) {
+        rtc_write(0);
+    }
+#endif
+    NVIC_ClearPendingIRQ(RTC_IRQn);
+    NVIC_DisableIRQ(RTC_IRQn);
+    NVIC_SetVector(RTC_IRQn, (uint32_t)RTC_IRQHandler);
+    NVIC_EnableIRQ(RTC_IRQn);
+#endif
 }
 
 void rtc_free(void)
@@ -230,4 +260,50 @@ void rtc_write(time_t t)
     HAL_RTC_SetTime(&RtcHandle, &timeStruct, FORMAT_BIN);
 }
 
+#if DEVICE_LOWPOWERTIMER
+
+static void RTC_IRQHandler(void)
+{
+    HAL_RTCEx_WakeUpTimerIRQHandler(&RtcHandle);
+}
+
+void HAL_RTCEx_WakeUpTimerEventCallback(RTC_HandleTypeDef *hrtc)
+{
+    if (irq_handler) {
+        // Fire the user callback
+        irq_handler();
+    }
+}
+
+void rtc_set_irq_handler(uint32_t handler)
+{
+    irq_handler = (void (*)(void))handler;
+}
+
+uint32_t rtc_read_subseconds(void)
+{
+    return 1000000.f * ((double)(RTC_SYNCH_PREDIV - RTC->SSR) / (RTC_SYNCH_PREDIV + 1));
+}
+
+void rtc_set_wake_up_timer(uint32_t delta)
+{
+    uint32_t wake_up_counter = delta / (2000000 / RTC_CLOCK);
+  
+    if (HAL_RTCEx_SetWakeUpTimer_IT(&RtcHandle, wake_up_counter,
+                                    RTC_WAKEUPCLOCK_RTCCLK_DIV2) != HAL_OK) {
+        error("Set wake up timer failed\n");
+    }
+}
+
+void rtc_deactivate_wake_up_timer(void)
+{
+    HAL_RTCEx_DeactivateWakeUpTimer(&RtcHandle);
+}
+
+void rtc_synchronize(void)
+{
+    HAL_RTC_WaitForSynchro(&RtcHandle);
+}
+#endif // DEVICE_LOWPOWERTIMER
+
 #endif

hal/targets/hal/TARGET_STM/TARGET_STM32L0/rtc_api_hal.h

@@ -0,0 +1,79 @@
+/* mbed Microcontroller Library
+*******************************************************************************
+* Copyright (c) 2016, STMicroelectronics
+* 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 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 STMicroelectronics nor the names of its contributors
+*    may be used to endorse or promote products derived from this software
+*    without specific prior written permission.
+*
+* 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.
+*******************************************************************************
+*/
+
+#ifndef MBED_RTC_API_HAL_H
+#define MBED_RTC_API_HAL_H
+
+#include <stdint.h>
+#include "rtc_api.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+/*
+ * Extend rtc_api.h
+ */
+
+/** Set the given function as handler of wakeup timer event.
+ *
+ * @param handler    The function to set as handler
+ */
+void rtc_set_irq_handler(uint32_t handler);
+
+/** Read the subsecond register.
+ *
+ * @return The remaining time as microseconds (0-999999)
+ */
+uint32_t rtc_read_subseconds(void);
+
+/** Program a wake up timer event in delta microseconds.
+ *
+ * @param delta    The time to wait
+ */
+void rtc_set_wake_up_timer(uint32_t delta);
+
+/** Disable the wake up timer event.
+ *
+ * The wake up timer use auto reload, you have to deactivate it manually.
+ */
+void rtc_deactivate_wake_up_timer(void);
+
+/** Synchronise the RTC shadow registers.
+ *
+ * Must be called after a deepsleep.
+ */
+void rtc_synchronize(void);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

hal/targets/hal/TARGET_STM/TARGET_STM32L0/sleep.c

@@ -28,6 +28,7 @@
  *******************************************************************************
  */
 #include "sleep_api.h"
+#include "rtc_api_hal.h"
 
 #if DEVICE_SLEEP
 
@@ -50,6 +51,10 @@ void deepsleep(void)
 
     // After wake-up from STOP reconfigure the PLL
     SetSysClock();
+    
+#if DEVICE_LOWPOWERTIMER
+    rtc_synchronize();
+#endif
 }
 
 #endif