api / mbed / trunk / PwmOut
PwmOut
class PwmOut : public Base
A pulse-width modulation digital output
Example
// Fade a led on.
#include "mbed.h"
PwmOut led(LED1);
int main() {
while(1) {
led = led + 0.01;
wait(0.2);
if(led == 1.0) {
led = 0;
}
}
}Note that on the LPC1768 and LPC2368, the PWMs all share the same period - if you change the period for one, you change it for all. Although routines that change the period maintain the duty cycle for its PWM, all other PWMs will require their duty cycle to be refreshed.
| PwmOut | A pulse-width modulation digital output |
| Functions | |
| PwmOut | Create a PwmOut connected to the specified pin |
| write | Set the ouput duty-cycle, specified as a percentage (float) |
| read | Return the current output duty-cycle setting, measured as a percentage (float) |
| period | Set the PWM period, specified in seconds (float), keeping the duty cycle the same. |
| period_ms | Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same. |
| period_us | Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same. |
| pulsewidth | Set the PWM pulsewidth, specified in seconds (float), keeping the period the same. |
| pulsewidth_ms | Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same. |
| pulsewidth_us | Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same. |
| operator= | A operator shorthand for write() |
| operator float() | An operator shorthand for read() |
write
void write( float value )
Set the ouput duty-cycle, specified as a percentage (float)
Variables
| value | A floating-point value representing the output duty-cycle, specified as a percentage. The value should lie between 0.0f (representing on 0%) and 1.0f (representing on 100%). Values outside this range will be saturated to 0.0f or 1.0f. |
read
float read()
Return the current output duty-cycle setting, measured as a percentage (float)
Variables
| returns | A floating-point value representing the current duty-cycle being output on the pin, measured as a percentage. The returned value will lie between 0.0f (representing on 0%) and 1.0f (representing on 100%). |
Note
This value may not match exactly the value set by a previous write.
operator=
PwmOut& operator= ( float value )
A operator shorthand for write()
operator float()
operator float()
An operator shorthand for read()
A pulse-width modulation digital output
class PwmOut : public Base
Create a PwmOut connected to the specified pin
PwmOut( PinName pin, const char * name = NULL )
Set the ouput duty-cycle, specified as a percentage (float)
void write( float value )
Return the current output duty-cycle setting, measured as a percentage (float)
float read()
Set the PWM period, specified in seconds (float), keeping the duty cycle the same.
void period( float seconds )
Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same.
void period_ms( int ms )
Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
void period_us( int us )
Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
void pulsewidth( float seconds )
Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
void pulsewidth_ms( int ms )
Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
void pulsewidth_us( int us )
A operator shorthand for write()
PwmOut& operator= ( float value )
An operator shorthand for read()
operator float()