Diff: api/AnalogOut.h

Revision:

144:ef7eb2e8f9f7

Parent:

0:9b334a45a8ff

--- a/api/AnalogOut.h	Tue Aug 02 14:07:36 2016 +0000
+++ b/api/AnalogOut.h	Fri Sep 02 15:07:44 2016 +0100
@@ -1,121 +1,146 @@
-/* mbed Microcontroller Library
- * Copyright (c) 2006-2013 ARM Limited
- *
- * 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.
- */
-#ifndef MBED_ANALOGOUT_H
-#define MBED_ANALOGOUT_H
-
-#include "platform.h"
-
-#if DEVICE_ANALOGOUT
-
-#include "analogout_api.h"
-
-namespace mbed {
-
-/** An analog output, used for setting the voltage on a pin
- *
- * Example:
- * @code
- * // Make a sawtooth output
- *
- * #include "mbed.h"
- *
- * AnalogOut tri(p18);
- * int main() {
- *     while(1) {
- *         tri = tri + 0.01;
- *         wait_us(1);
- *         if(tri == 1) {
- *             tri = 0;
- *         }
- *     }
- * }
- * @endcode
- */
-class AnalogOut {
-
-public:
-
-    /** Create an AnalogOut connected to the specified pin
-     *
-     *  @param AnalogOut pin to connect to (18)
-     */
-    AnalogOut(PinName pin) {
-        analogout_init(&_dac, pin);
-    }
-
-    /** Set the output voltage, specified as a percentage (float)
-     *
-     *  @param value A floating-point value representing the output voltage,
-     *    specified as a percentage. The value should lie between
-     *    0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
-     *    Values outside this range will be saturated to 0.0f or 1.0f.
-     */
-    void write(float value) {
-        analogout_write(&_dac, value);
-    }
-
-    /** Set the output voltage, represented as an unsigned short in the range [0x0, 0xFFFF]
-     *
-     *  @param value 16-bit unsigned short representing the output voltage,
-     *            normalised to a 16-bit value (0x0000 = 0v, 0xFFFF = 3.3v)
-     */
-    void write_u16(unsigned short value) {
-        analogout_write_u16(&_dac, value);
-    }
-
-    /** Return the current output voltage setting, measured as a percentage (float)
-     *
-     *  @returns
-     *    A floating-point value representing the current voltage being output on the pin,
-     *    measured as a percentage. The returned value will lie between
-     *    0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
-     *
-     *  @note
-     *    This value may not match exactly the value set by a previous write().
-     */
-    float read() {
-        return analogout_read(&_dac);
-    }
-
-#ifdef MBED_OPERATORS
-    /** An operator shorthand for write()
-     */
-    AnalogOut& operator= (float percent) {
-        write(percent);
-        return *this;
-    }
-
-    AnalogOut& operator= (AnalogOut& rhs) {
-        write(rhs.read());
-        return *this;
-    }
-
-    /** An operator shorthand for read()
-     */
-    operator float() {
-        return read();
-    }
-#endif
-
-protected:
-    dac_t _dac;
-};
-
-} // namespace mbed
-
-#endif
-
-#endif
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * 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.
+ */
+#ifndef MBED_ANALOGOUT_H
+#define MBED_ANALOGOUT_H
+
+#include "platform.h"
+
+#if DEVICE_ANALOGOUT
+
+#include "analogout_api.h"
+#include "PlatformMutex.h"
+
+namespace mbed {
+
+/** An analog output, used for setting the voltage on a pin
+ *
+ * @Note Synchronization level: Thread safe
+ *
+ * Example:
+ * @code
+ * // Make a sawtooth output
+ *
+ * #include "mbed.h"
+ *
+ * AnalogOut tri(p18);
+ * int main() {
+ *     while(1) {
+ *         tri = tri + 0.01;
+ *         wait_us(1);
+ *         if(tri == 1) {
+ *             tri = 0;
+ *         }
+ *     }
+ * }
+ * @endcode
+ */
+class AnalogOut {
+
+public:
+
+    /** Create an AnalogOut connected to the specified pin
+     *
+     *  @param AnalogOut pin to connect to (18)
+     */
+    AnalogOut(PinName pin) {
+        analogout_init(&_dac, pin);
+    }
+
+    /** Set the output voltage, specified as a percentage (float)
+     *
+     *  @param value A floating-point value representing the output voltage,
+     *    specified as a percentage. The value should lie between
+     *    0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
+     *    Values outside this range will be saturated to 0.0f or 1.0f.
+     */
+    void write(float value) {
+        lock();
+        analogout_write(&_dac, value);
+        unlock();
+    }
+
+    /** Set the output voltage, represented as an unsigned short in the range [0x0, 0xFFFF]
+     *
+     *  @param value 16-bit unsigned short representing the output voltage,
+     *            normalised to a 16-bit value (0x0000 = 0v, 0xFFFF = 3.3v)
+     */
+    void write_u16(unsigned short value) {
+        lock();
+        analogout_write_u16(&_dac, value);
+        unlock();
+    }
+
+    /** Return the current output voltage setting, measured as a percentage (float)
+     *
+     *  @returns
+     *    A floating-point value representing the current voltage being output on the pin,
+     *    measured as a percentage. The returned value will lie between
+     *    0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
+     *
+     *  @note
+     *    This value may not match exactly the value set by a previous write().
+     */
+    float read() {
+        lock();
+        float ret = analogout_read(&_dac);
+        unlock();
+        return ret;
+    }
+
+    /** An operator shorthand for write()
+     */
+    AnalogOut& operator= (float percent) {
+        // Underlying write call is thread safe
+        write(percent);
+        return *this;
+    }
+
+    AnalogOut& operator= (AnalogOut& rhs) {
+        // Underlying write call is thread safe
+        write(rhs.read());
+        return *this;
+    }
+
+    /** An operator shorthand for read()
+     */
+    operator float() {
+        // Underlying read call is thread safe
+        return read();
+    }
+
+    virtual ~AnalogOut() {
+        // Do nothing
+    }
+
+protected:
+
+    virtual void lock() {
+        _mutex.lock();
+    }
+
+    virtual void unlock() {
+        _mutex.unlock();
+    }
+
+    dac_t _dac;
+    PlatformMutex _mutex;
+};
+
+} // namespace mbed
+
+#endif
+
+#endif