mirror of https://github.com/ARMmbed/mbed-os.git
154 lines
3.8 KiB
C++
154 lines
3.8 KiB
C++
/* mbed Microcontroller Library
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* Copyright (c) 2006-2013 ARM Limited
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef MBED_ANALOGOUT_H
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#define MBED_ANALOGOUT_H
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#include "platform/platform.h"
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#if defined (DEVICE_ANALOGOUT) || defined(DOXYGEN_ONLY)
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#include "hal/analogout_api.h"
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#include "platform/PlatformMutex.h"
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namespace mbed {
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/** \addtogroup drivers */
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/** An analog output, used for setting the voltage on a pin
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*
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* @note Synchronization level: Thread safe
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*
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* Example:
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* @code
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* // Make a sawtooth output
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*
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* #include "mbed.h"
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*
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* AnalogOut tri(p18);
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* int main() {
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* while(1) {
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* tri = tri + 0.01;
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* wait_us(1);
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* if(tri == 1) {
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* tri = 0;
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* }
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* }
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* }
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* @endcode
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* @ingroup drivers
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*/
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class AnalogOut {
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public:
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/** Create an AnalogOut connected to the specified pin
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*
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* @param pin AnalogOut pin to connect to
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*/
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AnalogOut(PinName pin) {
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analogout_init(&_dac, pin);
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}
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/** Set the output voltage, specified as a percentage (float)
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*
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* @param value A floating-point value representing the output voltage,
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* specified as a percentage. The value should lie between
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* 0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
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* Values outside this range will be saturated to 0.0f or 1.0f.
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*/
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void write(float value) {
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lock();
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analogout_write(&_dac, value);
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unlock();
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}
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/** Set the output voltage, represented as an unsigned short in the range [0x0, 0xFFFF]
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*
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* @param value 16-bit unsigned short representing the output voltage,
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* normalised to a 16-bit value (0x0000 = 0v, 0xFFFF = 3.3v)
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*/
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void write_u16(unsigned short value) {
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lock();
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analogout_write_u16(&_dac, value);
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unlock();
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}
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/** Return the current output voltage setting, measured as a percentage (float)
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*
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* @returns
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* A floating-point value representing the current voltage being output on the pin,
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* measured as a percentage. The returned value will lie between
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* 0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
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*
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* @note
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* This value may not match exactly the value set by a previous write().
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*/
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float read() {
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lock();
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float ret = analogout_read(&_dac);
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unlock();
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return ret;
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}
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/** An operator shorthand for write()
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* \sa AnalogOut::write()
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*/
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AnalogOut& operator= (float percent) {
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// Underlying write call is thread safe
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write(percent);
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return *this;
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}
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/** An operator shorthand for write()
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* \sa AnalogOut::write()
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*/
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AnalogOut& operator= (AnalogOut& rhs) {
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// Underlying write call is thread safe
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write(rhs.read());
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return *this;
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}
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/** An operator shorthand for read()
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* \sa AnalogOut::read()
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*/
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operator float() {
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// Underlying read call is thread safe
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return read();
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}
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virtual ~AnalogOut() {
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// Do nothing
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}
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protected:
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virtual void lock() {
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_mutex.lock();
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}
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virtual void unlock() {
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_mutex.unlock();
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}
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dac_t _dac;
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PlatformMutex _mutex;
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};
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} // namespace mbed
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#endif
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#endif
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