Diff: mbed/drivers/AnalogOut.h

Revision:

6:40e873bbc5f7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed/drivers/AnalogOut.h	Thu Mar 16 21:58:09 2017 +0900
@@ -0,0 +1,150 @@
+/* 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/platform.h"
+
+#if DEVICE_ANALOGOUT
+
+#include "hal/analogout_api.h"
+#include "platform/PlatformMutex.h"
+
+namespace mbed {
+/** \addtogroup drivers */
+/** @{*/
+
+/** 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
+
+/** @}*/