static boolean initPWM(const IOPin* pin, uint32_t deciHertz){
const TimerCompare* channel = compareFromIOPin(pin);
if(channel==null){
setError(PWM_PIN_NOT_AVAILABLE);
return FALSE;
}
if(compareIsInUse(channel)){
setError(PWM_PIN_IN_USE);
return FALSE;
}
TIMER_MODE mode;
uint16_t icr;
uint16_t prescaler;
const Timer* timer = compareGetTimer(channel);
// Find the best PWM setting for 10kHz, with 128 steps
boolean valid = timerCalcPwm(timer, deciHertz, 128, &mode, &icr, &prescaler);
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
if(!timerIsInUse(timer)){
timerSetMode(timer,mode);
if(modeIsICR(mode)){
// Set the ICR
PORT icrPort = pgm_read_word(&timer->pgm_icr);
_SFR_MEM16(icrPort)=icr;
}
}
// Make it an output pin and set high for brake
pin_make_output(pin,TRUE);
// Use inverting PWM
compareSetOutputMode(channel,CHANNEL_MODE_INVERTING);
// Mark the channels as in use
compareAttach(channel,&nullTimerCompareCallback,0,null);
// Do this last as it then turns on the timer
timerSetPrescaler(timer,prescaler);
}
return valid;
}
// Set up PWM on the given pin
boolean pwmInitDeciHertz(const IOPin* pin, uint32_t deciHertz, DUTY_CYCLE 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
if(compareIsInUse(channel)){
setError(PWM_PIN_IN_USE);
}else{
// The pin is valid and available
TIMER_MODE mode;
uint16_t icr;
uint16_t prescaler;
const Timer* timer = compareGetTimer(channel);
// Find the best PWM setting
boolean valid = timerCalcPwm(timer, deciHertz, 100, &mode, &icr, &prescaler);
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
if(!timerIsInUse(timer)){
timerSetMode(timer,mode);
if(modeIsICR(mode)){
// Set the ICR
PORT icrPort = pgm_read_word(&timer->pgm_icr);
_SFR_MEM16(icrPort)=icr;
}
}else{
// Can't change the prescaler so just use the existing
prescaler = timerGetPrescaler(timer);
}
// 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 = TimerGetPwmDeciHertz(timer);
}
rtn = TRUE;
}
}
}
return rtn;
}
