Diff: source/drivers/MicroBitThermometer.cpp

Revision:

1:8aa5cdb4ab67

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/source/drivers/MicroBitThermometer.cpp	Thu Apr 07 01:33:22 2016 +0100
@@ -0,0 +1,278 @@
+/*
+The MIT License (MIT)
+
+Copyright (c) 2016 British Broadcasting Corporation.
+This software is provided by Lancaster University by arrangement with the BBC.
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+*/
+
+#include "MicroBitConfig.h"
+#include "MicroBitThermometer.h"
+#include "MicroBitSystemTimer.h"
+#include "MicroBitFiber.h"
+
+/*
+ * The underlying Nordic libraries that support BLE do not compile cleanly with the stringent GCC settings we employ
+ * If we're compiling under GCC, then we suppress any warnings generated from this code (but not the rest of the DAL)
+ * The ARM cc compiler is more tolerant. We don't test __GNUC__ here to detect GCC as ARMCC also typically sets this
+ * as a compatability option, but does not support the options used...
+ */
+#if !defined(__arm)
+#pragma GCC diagnostic ignored "-Wunused-function"
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#endif
+
+#include "nrf_soc.h"
+#include "nrf_sdm.h"
+
+/*
+ * Return to our predefined compiler settings.
+ */
+#if !defined(__arm)
+#pragma GCC diagnostic pop
+#endif
+
+/**
+  * Constructor.
+  * Create new MicroBitThermometer that gives an indication of the current temperature.
+  *
+  * @param _storage an instance of MicroBitStorage used to persist temperature offset data
+  *
+  * @param id the unique EventModel id of this component. Defaults to MICROBIT_ID_THERMOMETER.
+  *
+  * @code
+  * MicroBitStorage storage;
+  * MicroBitThermometer thermometer(storage);
+  * @endcode
+  */
+MicroBitThermometer::MicroBitThermometer(MicroBitStorage& _storage, uint16_t id) :
+    storage(&_storage)
+{
+    this->id = id;
+    this->samplePeriod = MICROBIT_THERMOMETER_PERIOD;
+    this->sampleTime = 0;
+    this->offset = 0;
+
+    KeyValuePair *tempCalibration =  storage->get(ManagedString("tempCal"));
+
+    if(tempCalibration != NULL)
+    {
+        memcpy(&offset, tempCalibration->value, sizeof(int16_t));
+        delete tempCalibration;
+    }
+}
+
+/**
+  * Constructor.
+  * Create new MicroBitThermometer that gives an indication of the current temperature.
+  *
+  * @param id the unique EventModel id of this component. Defaults to MICROBIT_ID_THERMOMETER.
+  *
+  * @code
+  * MicroBitThermometer thermometer;
+  * @endcode
+  */
+MicroBitThermometer::MicroBitThermometer(uint16_t id) :
+    storage(NULL)
+{
+    this->id = id;
+    this->samplePeriod = MICROBIT_THERMOMETER_PERIOD;
+    this->sampleTime = 0;
+    this->offset = 0;
+}
+
+/**
+  * Gets the current temperature of the microbit.
+  *
+  * @return the current temperature, in degrees celsius.
+  *
+  * @code
+  * thermometer.getTemperature();
+  * @endcode
+  */
+int MicroBitThermometer::getTemperature()
+{
+    updateSample();
+    return temperature - offset;
+}
+
+
+/**
+  * Updates the temperature sample of this instance of MicroBitThermometer
+  * only if isSampleNeeded() indicates that an update is required.
+  *
+  * This call also will add the thermometer to fiber components to receive
+  * periodic callbacks.
+  *
+  * @return MICROBIT_OK on success.
+  */
+int MicroBitThermometer::updateSample()
+{
+    if(!(status & MICROBIT_THERMOMETER_ADDED_TO_IDLE))
+    {
+        // If we're running under a fiber scheduer, register ourselves for a periodic callback to keep our data up to date.
+        // Otherwise, we do just do this on demand, when polled through our read() interface.
+        fiber_add_idle_component(this);
+        status |= MICROBIT_THERMOMETER_ADDED_TO_IDLE;
+    }
+
+    // check if we need to update our sample...
+    if(isSampleNeeded())
+    {
+        int32_t processorTemperature;
+        uint8_t sd_enabled;
+
+        // For now, we just rely on the nrf senesor to be the most accurate.
+        // The compass module also has a temperature sensor, and has the lowest power consumption, so will run the cooler...
+        // ...however it isn't trimmed for accuracy during manufacture, so requires calibration.
+
+        sd_softdevice_is_enabled(&sd_enabled);
+
+        if (sd_enabled)
+        {
+            // If Bluetooth is enabled, we need to go through the Nordic software to safely do this
+            sd_temp_get(&processorTemperature);
+        }
+        else
+        {
+            // Othwerwise, we access the information directly...
+            uint32_t *TEMP = (uint32_t *)0x4000C508;
+
+            NRF_TEMP->TASKS_START = 1;
+
+            while (NRF_TEMP->EVENTS_DATARDY == 0);
+
+            NRF_TEMP->EVENTS_DATARDY = 0;
+
+            processorTemperature = *TEMP;
+
+            NRF_TEMP->TASKS_STOP = 1;
+        }
+
+
+        // Record our reading...
+        temperature = processorTemperature / 4;
+
+        // Schedule our next sample.
+        sampleTime = system_timer_current_time() + samplePeriod;
+
+        // Send an event to indicate that we'e updated our temperature.
+        MicroBitEvent e(id, MICROBIT_THERMOMETER_EVT_UPDATE);
+    }
+
+    return MICROBIT_OK;
+};
+
+/**
+  * Indicates if we'd like some processor time to sense the temperature.
+  *
+  * @returns 1 if we'd like some processor time, 0 otherwise.
+  */
+int MicroBitThermometer::isIdleCallbackNeeded()
+{
+    return isSampleNeeded();
+}
+
+/**
+  * Periodic callback from MicroBit idle thread.
+  */
+void MicroBitThermometer::idleTick()
+{
+    updateSample();
+}
+
+/**
+  * Determines if we're due to take another temperature reading
+  *
+  * @return 1 if we're due to take a temperature reading, 0 otherwise.
+  */
+int MicroBitThermometer::isSampleNeeded()
+{
+    return  system_timer_current_time() >= sampleTime;
+}
+
+/**
+  * Set the sample rate at which the temperatureis read (in ms).
+  *
+  * The default sample period is 1 second.
+  *
+  * @param period the requested time between samples, in milliseconds.
+  *
+  * @note the temperature is always read in the background, and is only updated
+  * when the processor is idle, or when the temperature is explicitly read.
+  */
+void MicroBitThermometer::setPeriod(int period)
+{
+    updateSample();
+    samplePeriod = period;
+}
+
+/**
+  * Reads the currently configured sample rate of the thermometer.
+  *
+  * @return The time between samples, in milliseconds.
+  */
+int MicroBitThermometer::getPeriod()
+{
+    return samplePeriod;
+}
+
+/**
+  * Set the value that is used to offset the raw silicon temperature.
+  *
+  * @param offset the offset for the silicon temperature
+  *
+  * @return MICROBIT_OK on success
+  */
+int MicroBitThermometer::setOffset(int offset)
+{
+    if(this->storage != NULL)
+        this->storage->put(ManagedString("tempCal"), (uint8_t *)&offset);
+
+    this->offset = offset;
+
+    return MICROBIT_OK;
+}
+
+/**
+  * Retreive the value that is used to offset the raw silicon temperature.
+  *
+  * @return the current offset.
+  */
+int MicroBitThermometer::getOffset()
+{
+    return offset;
+}
+
+/**
+  * This member function fetches the raw silicon temperature, and calculates
+  * the value used to offset the raw silicon temperature based on a given temperature.
+  *
+  * @param calibrationTemp the temperature used to calculate the raw silicon temperature
+  * offset.
+  *
+  * @return MICROBIT_OK on success
+  */
+int MicroBitThermometer::setCalibration(int calibrationTemp)
+{
+    updateSample();
+    return setOffset(temperature - calibrationTemp);
+}