Creates square-wave frequency output on pin p22. Custom frequency between 1Hz and 48 MHz. (LPC 1768)
Creates square-wave frequency output on pin22 with custom frequency.
Tested for frequencies from 1Hz to 48MHz. The accuracy depends heavily on the frequency - at 12, 24, 48 MHz the frequency deviation is less than 1%, but at 20 MHz it is about 20%.
Uses Library FastPWM ( http://mbed.org/users/Sissors/code/FastPWM/ ). For LPC 1768.
How to use this Library:
#include "mbed.h" #include "PwmOscillator.h" PwmOscillator oscillator; DigitalOut led1(LED1); int main() { oscillator.initWithFrequency(8000000); // initialize oscillator instance (pin p22) with custom frequency, here: 8MHz led1=1; // optional: indicator LED shows that oscillator is running oscillator.start(); // start oscillator wait(5); // optional: oscillator is running 5 seconds oscillator.stop(); // stop oscillator led1=0; }
Diff: PwmOscillator.h
- Revision:
- 1:4bbb380a1089
- Parent:
- 0:9e0f295a55a4
- Child:
- 2:d9fea7c1fc8d
--- a/PwmOscillator.h Fri Dec 14 14:34:22 2012 +0000 +++ b/PwmOscillator.h Fri Dec 14 14:39:48 2012 +0000 @@ -1,7 +1,7 @@ #include "mbed.h" -/** Creates square-wave frequency output on pin22 with custom frequency. Tested for frequency range from 1Hz to 48MHz. - * The accuracy is depends on the frequency - at 12, 24, 48 MHz the frequency deviation is less than 1% but at 20 MHz it is about 20%. +/** Creates square-wave frequency output on pin22 with custom frequency. Tested for frequencies from 1Hz to 48MHz. + * The accuracy depends heavily on the frequency - at 12, 24, 48 MHz the frequency deviation is less than 1%, but at 20 MHz it is about 20%. * Uses Library FastPWM ( http://mbed.org/users/Sissors/code/FastPWM/ ). */ class PwmOscillator {