Diff: low_power.cpp

Revision:

1:4f2c412dc013

Child:

3:442c9afc0229

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/low_power.cpp	Mon Apr 10 11:40:13 2017 +0100
@@ -0,0 +1,216 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 u-blox
+ *
+ * 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.
+ */
+
+/**
+ * @file low_power.cpp
+ * This file defines a class intended to assist with obtaining lowest power
+ * operation on an STM32F437 microprocessor.
+ */
+
+// Define this to print debug information
+//#define DEBUG_LOW_POWER
+
+#include <mbed.h>
+#include <low_power.h>
+#ifdef TARGET_STM
+#include <stm32f4xx_hal_pwr.h>
+#include <stm32f4xx_hal_rcc.h>
+#endif
+
+#ifdef DEBUG_LOW_POWER
+# include <stdio.h>
+#endif
+
+// ----------------------------------------------------------------
+// COMPILE-TIME MACROS
+// ----------------------------------------------------------------
+
+/// Location of backup SRAM in memory (on STM23F4, has no effect otherwise).
+#define BACKUP_SRAM_START_ADDRESS ((uint32_t *) ((uint32_t) BKPSRAM_BASE))
+
+// ----------------------------------------------------------------
+// PRIVATE VARIABLES
+// ----------------------------------------------------------------
+
+// ----------------------------------------------------------------
+// PRIVATE FUNCTIONS
+// ----------------------------------------------------------------
+
+/// Check whether an interrupt is enabled or not.
+inline uint32_t LowPower::myNVIC_GetEnableIRQ(IRQn_Type IRQn)
+{
+    if ((int32_t)(IRQn) >= 0) {
+        return((uint32_t)(((NVIC->ISER[(((uint32_t)(int32_t)IRQn) >> 5UL)] & (1UL << (((uint32_t)(int32_t)IRQn) & 0x1FUL))) != 0UL) ? 1UL : 0UL));
+    } else {
+        return(0U);
+    }
+}
+
+//----------------------------------------------------------------
+// PUBLIC FUNCTIONS
+// ----------------------------------------------------------------
+
+/// Constructor.
+LowPower::LowPower(void)
+{
+#ifdef TARGET_STM
+    // Enable back-up SRAM access, see section 5.1.2 of the STM32F437
+    // detailed manual and stm32f4xx_hal_pwr.c
+    __HAL_RCC_PWR_CLK_ENABLE();
+    HAL_PWR_EnableBkUpAccess();
+    __HAL_RCC_BKPSRAM_CLK_ENABLE();
+    
+    // Determine if we've already been active
+    if (!__HAL_PWR_GET_FLAG(PWR_FLAG_BRR)) {
+        // If the backup regulator is not running, we've not woken
+        // up from Standby with data in there and so we
+        // should zero the backup SRAM to clean it up.
+        memset (BACKUP_SRAM_START_ADDRESS, 0, BACKUP_SRAM_SIZE);
+    }
+#endif        
+}
+
+/// Destructor.
+LowPower::~LowPower(void)
+{
+}
+
+/// Enter Stop mode.
+void LowPower::enterStop(uint32_t stopPeriodMilliseconds)
+{
+    if (stopPeriodMilliseconds > 0) {
+        // If the RTC is not running, call set_time with
+        // a value of zero to kick it into life
+        if (time(NULL) <= 0) {
+            set_time(0);
+        }
+
+#ifdef DEBUG_LOW_POWER
+        time_t timeNow = time(NULL);
+        time_t timeThen = timeNow + stopPeriodMilliseconds / 1000;
+        char buf[32];
+        strftime(buf, sizeof (buf), "%Y-%m-%d %H:%M:%S", localtime(&timeThen));
+        printf ("LowPower: going to Stop mode for %.3f second(s) (will awake at ~%s).\n", 
+                (float) stopPeriodMilliseconds / 1000, buf);
+        wait_ms(100); // Let printf leave the building
+#endif
+
+        // Set the RTC alarm
+        WakeUp::set_ms(stopPeriodMilliseconds);
+        // Now enter Stop mode, allowing flash to power down
+        // also if we can
+#ifdef TARGET_STM
+        HAL_PWREx_EnableFlashPowerDown();
+#endif        
+        hal_deepsleep();
+#ifdef TARGET_STM
+        HAL_PWREx_DisableFlashPowerDown();
+#endif
+    }
+}
+
+/// Enter Standby mode.
+void LowPower::enterStandby(uint32_t standbyPeriodMilliseconds, bool powerDownBackupSram)
+{
+    if (standbyPeriodMilliseconds > 0) {
+        // If time the RTC is not running, call set_time with
+        // a value of zero to kick it into life
+        if (time(NULL) <= 0) {
+            set_time(0);
+        }
+        
+#ifdef TARGET_STM
+        // Set the backup regulator (for backup SRAM) into the right state
+        if (powerDownBackupSram) {
+            HAL_PWREx_DisableBkUpReg();
+        } else {
+            HAL_PWREx_EnableBkUpReg();
+        }
+#endif
+        
+#ifdef DEBUG_LOW_POWER
+        time_t timeNow = time(NULL);
+        time_t timeThen = timeNow + standbyPeriodMilliseconds / 1000;
+        char buf[32];
+        strftime(buf, sizeof (buf), "%Y-%m-%d %H:%M:%S", localtime(&timeThen));
+        printf ("LowPower: going to Standby mode for %.3f second(s) (will awake at ~%s).\n", 
+                (float) standbyPeriodMilliseconds / 1000, buf);
+        wait_ms(100); // Let printf leave the building
+#endif
+
+        // Set the RTC alarm
+        WakeUp::set_ms(standbyPeriodMilliseconds);
+#ifdef TARGET_STM
+        // Now enter Standby mode, clearing the wake-up flag first
+        // in case we've done this before
+        PWR->CR = PWR_CR_CWUF;
+        HAL_PWR_EnterSTANDBYMode();
+#else
+        MBED_ASSERT(false);
+#endif
+    }
+}
+
+/// Get the number of user interrupts that are enabled.
+int32_t LowPower::numUserInterruptsEnabled(uint8_t *pList, uint32_t sizeOfList)
+{
+    int32_t userInterruptsEnabled = 0;
+    uint8_t *pEndOfList = pList + sizeOfList;
+    
+#ifdef DEBUG_LOW_POWER
+    printf ("Checking enabled interrupts...");
+#endif
+    for (uint8_t x = 0; x < NVIC_NUM_VECTORS - NVIC_USER_IRQ_OFFSET; x++) {
+        if (myNVIC_GetEnableIRQ((IRQn_Type) x)) {
+            userInterruptsEnabled++;
+            if ((pList != NULL) && (pList < pEndOfList)) {
+                *pList = x;
+                pList++;
+            }
+#ifdef DEBUG_LOW_POWER
+            printf (" %d", x);
+#endif
+        }
+    }
+
+#ifdef DEBUG_LOW_POWER
+    if (userInterruptsEnabled == 0) {
+        printf (" (none were enabled)");
+    }
+    printf (".\n");
+#endif
+    
+    return userInterruptsEnabled;
+}
+
+/// Exit debug mode.
+void LowPower::exitDebugMode(void)
+{
+#ifdef TARGET_STM
+    // If this is a power on reset, do a system
+    // reset to get us out of our debug-mode 
+    // entanglement with the debug chip on the
+    // mbed board
+    if (__HAL_RCC_GET_FLAG(RCC_FLAG_PORRST)) {
+        __HAL_RCC_CLEAR_RESET_FLAGS();
+        NVIC_SystemReset();
+    }
+#else
+    MBED_ASSERT(false);
+#endif    
+}
+
+// End Of File