AnalogOut.h

00001 /* mbed Microcontroller Library - AnalogOut
00002  * Copyright (c) 2006-2011 ARM Limited. All rights reserved.
00003  */ 
00004  
00005 #ifndef MBED_ANALOGOUT_H
00006 #define MBED_ANALOGOUT_H
00007 
00008 #include "device.h"
00009 
00010 #if DEVICE_ANALOGOUT
00011 
00012 #include "platform.h"
00013 #include "PinNames.h"
00014 #include "PeripheralNames.h"
00015 #include "Base.h"
00016 
00017 namespace mbed {
00018 
00019 /* Class: AnalogOut
00020  *  An analog output, used for setting the voltage on a pin
00021  *
00022  * Example:
00023  * > // Make a sawtooth output
00024  * > 
00025  * > #include "mbed.h"
00026  * > 
00027  * > AnalogOut tri(p18);
00028  * > int main() {
00029  * >     while(1) {
00030  * >         tri = tri + 0.01;
00031  * >         wait_us(1);
00032  * >         if(tri == 1) {
00033  * >             tri = 0;
00034  * >         }
00035  * >     }
00036  * > }
00037  */
00038 class AnalogOut : public Base {
00039 
00040 public:
00041 
00042     /* Constructor: AnalogOut
00043      *  Create an AnalogOut connected to the specified pin
00044      * 
00045      * Variables:
00046      *  pin - AnalogOut pin to connect to (18)
00047      */
00048     AnalogOut(PinName pin, const char *name = NULL);
00049     
00050     /* Function: write
00051      *  Set the output voltage, specified as a percentage (float)
00052      *
00053      * Variables:
00054      *  percent - A floating-point value representing the output voltage, 
00055      *    specified as a percentage. The value should lie between
00056      *    0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
00057      *    Values outside this range will be saturated to 0.0f or 1.0f.   
00058      */
00059     void write(float value);
00060     
00061     /* Function: write_u16
00062      *  Set the output voltage, represented as an unsigned short in the range [0x0, 0xFFFF]
00063      *
00064      * Variables:
00065      *  value - 16-bit unsigned short representing the output voltage,
00066      *            normalised to a 16-bit value (0x0000 = 0v, 0xFFFF = 3.3v)
00067      */
00068     void write_u16(unsigned short value);
00069 
00070     /* Function: read
00071      *  Return the current output voltage setting, measured as a percentage (float)
00072      *
00073      * Variables:
00074      *  returns - A floating-point value representing the current voltage being output on the pin, 
00075      *    measured as a percentage. The returned value will lie between
00076      *    0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
00077      *
00078      * Note:
00079      *  This value may not match exactly the value set by a previous <write>.
00080      */ 
00081     float read();
00082 
00083 
00084 #ifdef MBED_OPERATORS
00085     /* Function: operator=
00086      *  An operator shorthand for <write()>
00087      */
00088     AnalogOut& operator= (float percent);
00089     AnalogOut& operator= (AnalogOut& rhs);
00090 
00091     /* Function: operator float()
00092      *  An operator shorthand for <read()>
00093      */ 
00094     operator float();
00095 #endif
00096 
00097 #ifdef MBED_RPC
00098     virtual const struct rpc_method *get_rpc_methods();
00099     static struct rpc_class *get_rpc_class();
00100 #endif
00101 
00102 protected:
00103 
00104     DACName _dac;
00105 
00106 };
00107 
00108 } // namespace mbed
00109 
00110 #endif
00111 
00112 #endif