// Set up PWM on the given pin
boolean pwmInitDeciHertz(const IOPin* pin, uint32_t deciHertz, PERCENTAGE duty, uint32_t* actualDeciHertz){
boolean rtn = FALSE;
const TimerCompare* channel = compareFromIOPin(pin);
if(channel==null){
setError(PWM_PIN_NOT_AVAILABLE);
}else{
// The pin is valid
// The pin is valid and available
TIMER_MODE mode;
uint16_t icr;
uint16_t prescaler;
uint32_t actual;
const Timer* timer = compareGetTimer(channel);
// Find the best PWM setting
boolean valid = timerCalcPwm(timer, deciHertz, 100, &mode, &icr, &prescaler, &actual);
if(!valid){
// There is no PWM setting that is valid
setError( (timerIsInUse(timer)) ? PWM_TIMER_IN_USE : TIMER_HAS_NO_PWM );
}else{
// Lets set up the PWM
timerSetMode(timer,mode);
if(modeIsICR(mode)){
// Set the ICR
PORT icrPort = pgm_read_word(&timer->pgm_icr);
_SFR_MEM16(icrPort)=icr;
}
// Mark the channel as in use
// compareAttach(channel,&nullTimerCompareCallback,0,null);
// Turn the pin into an output, low
pin_make_output(pin, FALSE);
// Turn on the PWM pin output
compareSetOutputMode(channel, CHANNEL_MODE_NON_INVERTING);
// Turn on the timer
timerSetPrescaler(timer,prescaler);
// Set the initial duty cycle
pwmSetDutyCycle(pin,duty);
// Set the return value
if(actualDeciHertz){
*actualDeciHertz = actual;
}
rtn = TRUE;
}
}
return rtn;
}
static void soundOn(void){
#if !defined(_WINDOWS_)
pwmSetDutyCycle(pwmPin,50); // Set 50% duty cycle
// cli();
#endif
// initialise random number seed
seed[0]=0xecu;
seed[1]=7;
seed[2]=0xcfu;
}
int main(void)
{
#ifndef CFG_PWM
#ERROR "CFG_PWM must be enabled in projectconfig.h for this example."
#endif
// Configure cpu and mandatory peripherals
// PWM is initialised in systemInit and defaults to using P1.9
systemInit();
// Set duty cycle to 50% for square wave output
pwmSetDutyCycle(50);
// Frequency can be set anywhere from 2khz and 10khz (4khz is loudest)
// Note: Since this is a 16-bit timer, make sure the delay is not
// greater than 0xFFFF (65535), though anything 2khz and higher
// is within an acceptable range
// The piezo buzzer used for this example is the PS1240, available at
// http://www.adafruit.com/index.php?main_page=product_info&cPath=35&products_id=160
pwmSetFrequencyInTicks(CFG_CPU_CCLK / 2000);
uint32_t currentSecond, lastSecond;
currentSecond = lastSecond = 0;
while (1)
{
// Beep the piezo buzzer very briefly once per second, toggling the LED at the same time
currentSecond = systickGetSecondsActive();
// Make sure that at least one second has passed
if (currentSecond != lastSecond)
{
// Update the second tracker
lastSecond = currentSecond;
// Set the LED state and buzzer loudness depending on the current LED state
if (gpioGetValue(CFG_LED_PORT, CFG_LED_PIN) == CFG_LED_OFF)
{
pwmSetFrequencyInTicks(CFG_CPU_CCLK / 4000); // 4khz (louder)
pwmStartFixed(200); // 2x as long as @ 2khz since it's 2x faster
gpioSetValue (CFG_LED_PORT, CFG_LED_PIN, CFG_LED_ON); // Turn the LED on
}
else
{
pwmSetFrequencyInTicks(CFG_CPU_CCLK / 2000); // 2khz (softer)
pwmStartFixed(100);
gpioSetValue (CFG_LED_PORT, CFG_LED_PIN, CFG_LED_OFF); // Turn the LED off
}
}
}
return 0;
}
static void soundOff(void){
#if !defined(_WINDOWS_)
// sei();
pwmSetDutyCycle(pwmPin,50); // Set 50% duty cycle
#endif
}
