gcc4mbed/external/mbed/PwmOut.h

   1 /* mbed Microcontroller Library - PwmOut
   2  * Copyright (c) 2007-2011 ARM Limited. All rights reserved.
   3  */
   4
   5 #ifndef MBED_PWMOUT_H
   6 #define MBED_PWMOUT_H
   7
   8 #include "device.h"
   9
  10 #if DEVICE_PWMOUT
  11
  12 #include "platform.h"
  13 #include "PinNames.h"
  14 #include "PeripheralNames.h"
  15 #include "Base.h"
  16
  17 namespace mbed {
  18
  19 /* Class: PwmOut
  20  *  A pulse-width modulation digital output
  21  *
  22  * Example
  23  * > // Fade a led on.
  24  * > #include "mbed.h"
  25  * >
  26  * > PwmOut led(LED1);
  27  * >
  28  * > int main() {
  29  * >     while(1) {
  30  * >         led = led + 0.01;
  31  * >         wait(0.2);
  32  * >         if(led == 1.0) {
  33  * >             led = 0;
  34  * >         }
  35  * >     }
  36  * > }
  37  *
  38  *  Note that on the LPC1768 and LPC2368, the PWMs all share the same
  39  *  period - if you change the period for one, you change it for all.
  40  *  Although routines that change the period maintain the duty cycle
  41  *  for its PWM, all other PWMs will require their duty cycle to be
  42  *  refreshed.
  43  */
  44 class PwmOut : public Base {
  45
  46 public:
  47
  48     /* Constructor: PwmOut
  49      *  Create a PwmOut connected to the specified pin
  50      *
  51      * Variables:
  52      *  pin - PwmOut pin to connect to
  53      */
  54     PwmOut(PinName pin, const char *name = NULL);
  55
  56     /* Function: write
  57      *  Set the ouput duty-cycle, specified as a percentage (float)
  58      *
  59      * Variables:
  60      *  value - A floating-point value representing the output duty-cycle,
  61      *    specified as a percentage. The value should lie between
  62      *    0.0f (representing on 0%) and 1.0f (representing on 100%).
  63      *    Values outside this range will be saturated to 0.0f or 1.0f.
  64      */
  65     void write(float value);
  66
  67     /* Function: read
  68      *  Return the current output duty-cycle setting, measured as a percentage (float)
  69      *
  70      * Variables:
  71      *  returns - A floating-point value representing the current duty-cycle being output on the pin,
  72      *    measured as a percentage. The returned value will lie between
  73      *    0.0f (representing on 0%) and 1.0f (representing on 100%).
  74      *
  75      * Note:
  76      *  This value may not match exactly the value set by a previous <write>.
  77      */
  78     float read();
  79
  80     /* Function: period
  81      *  Set the PWM period, specified in seconds (float), keeping the
  82      *  duty cycle the same.
  83      *
  84      *  Note:
  85      *   The resolution is currently in microseconds; periods smaller than this
  86      *   will be set to zero.
  87      */
  88     void period(float seconds);
  89
  90     /* Function: period_ms
  91      *  Set the PWM period, specified in milli-seconds (int), keeping the
  92      *  duty cycle the same.
  93      */
  94     void period_ms(int ms);
  95
  96     /* Function: period_us
  97      *  Set the PWM period, specified in micro-seconds (int), keeping the
  98      *  duty cycle the same.
  99      */
 100     void period_us(int us);
 101
 102     /* Function: pulsewidth
 103      *  Set the PWM pulsewidth, specified in seconds (float), keeping the
 104      *  period the same.
 105      */
 106     void pulsewidth(float seconds);
 107
 108     /* Function: pulsewidth_ms
 109      *  Set the PWM pulsewidth, specified in milli-seconds (int), keeping
 110      *  the period the same.
 111      */
 112     void pulsewidth_ms(int ms);
 113
 114     /* Function: pulsewidth_us
 115      *  Set the PWM pulsewidth, specified in micro-seconds (int), keeping
 116      *  the period the same.
 117      */
 118     void pulsewidth_us(int us);
 119
 120 #ifdef MBED_OPERATORS
 121     /* Function: operator=
 122      *  A operator shorthand for <write()>
 123      */
 124     PwmOut& operator= (float value);
 125     PwmOut& operator= (PwmOut& rhs);
 126
 127     /* Function: operator float()
 128      *  An operator shorthand for <read()>
 129      */
 130     operator float();
 131 #endif
 132
 133 #ifdef MBED_RPC
 134     virtual const struct rpc_method *get_rpc_methods();
 135     static struct rpc_class *get_rpc_class();
 136 #endif
 137
 138 protected:
 139
 140     PWMName _pwm;
 141
 142 };
 143
 144 } // namespace mbed
 145
 146 #endif
 147
 148 #endif