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mbed-classic/api/AnalogOut.h

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/* 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