/**
* @brief Disables a PWM channel.
* @pre The PWM unit must have been activated using @p pwmStart().
* @post The channel is disabled and its output line returned to the
* idle state.
* @note Depending on the hardware implementation this function has
* effect starting on the next cycle (recommended implementation)
* or immediately (fallback implementation).
*
* @param[in] pwmp pointer to a @p PWMDriver object
* @param[in] channel PWM channel identifier (0...PWM_CHANNELS-1)
*
* @notapi
*/
void pwm_lld_disable_channel(PWMDriver *pwmp, pwmchannel_t channel)
{
uint8_t i = timer_index(pwmp);
config_channel(regs_table[i].tccra,
7 - 2*channel,
6 - 2*channel,
PWM_OUTPUT_DISABLED);
*regs_table[i].timsk &= ~(1 << (channel + 1));
}
/**
* @brief Enables a PWM channel.
* @pre The PWM unit must have been activated using @p pwmStart().
* @post The channel is active using the specified configuration.
* @note Depending on the hardware implementation this function has
* effect starting on the next cycle (recommended implementation)
* or immediately (fallback implementation).
*
* @param[in] pwmp pointer to a @p PWMDriver object
* @param[in] channel PWM channel identifier (0...PWM_CHANNELS-1)
* @param[in] width PWM pulse width as clock pulses number
*
* @notapi
*/
void pwm_lld_enable_channel(PWMDriver *pwmp,
pwmchannel_t channel,
pwmcnt_t width)
{
uint16_t val = width;
if (val > MAX_PWM_VALUE)
val = MAX_PWM_VALUE;
#if AVR_PWM_USE_TIM2 || defined(__DOXYGEN__)
if (pwmp == &PWMD2) {
config_channel(&TCCR2A,
7 - 2*channel,
6 - 2*channel,
pwmp->config->channels[channel].mode);
TIMSK2 |= (1 << (channel + 1));
/* Timer 2 is 8 bit */
if (val > 0xFF)
val = 0xFF;
if (pwmp->config->channels[channel].callback) {
switch (channel) {
case 0: OCR2A = val; break;
case 1: OCR2B = val; break;
}
}
return;
}
#endif
uint8_t i = timer_index(pwmp);
config_channel(regs_table[i].tccra,
7 - 2*channel,
6 - 2*channel,
pwmp->config->channels[channel].mode);
volatile uint8_t *ocrh, *ocrl;
switch (channel) {
case 1:
ocrh = regs_table[i].ocrbh;
ocrl = regs_table[i].ocrbl;
break;
case 2:
ocrh = regs_table[i].ocrch;
ocrl = regs_table[i].ocrcl;
break;
default:
ocrh = regs_table[i].ocrah;
ocrl = regs_table[i].ocral;
}
*ocrh = val >> 8;
*ocrl = val & 0xFF;
*regs_table[i].tifr |= (1 << (channel + 1));
if (pwmp->config->channels[channel].callback)
*regs_table[i].timsk |= (1 << (channel + 1));
}
/**
* @brief Configures and activates the PWM peripheral.
*
* @param[in] pwmp pointer to the @p PWMDriver object
*
* @notapi
*/
void pwm_lld_start(PWMDriver *pwmp)
{
if (pwmp->state == PWM_STOP) {
#if AVR_PWM_USE_TIM2 || defined(__DOXYGEN__)
if (pwmp == &PWMD2) {
TCCR2B &= ~((1 << CS22) | (1 << CS21));
TCCR2B |= (1 << CS20);
if (pwmp->config->callback != NULL)
TIMSK2 |= (1 << TOIE2);
return;
}
#endif
/* TODO: support other prescaler options */
uint8_t i = timer_index(pwmp);
*regs_table[i].tccrb &= ~(1 << CS11);
*regs_table[i].tccrb |= (1 << CS12) | (1 << CS10);
*regs_table[i].timsk = (1 << TOIE1);
}
}
/**
* @brief Disables a channel de-activation edge notification.
* @pre The PWM unit must have been activated using @p pwmStart().
* @pre The channel must have been activated using @p pwmEnableChannel().
* @note If the notification is already disabled then the call has no effect.
*
* @param[in] pwmp pointer to a @p PWMDriver object
* @param[in] channel PWM channel identifier (0...channels-1)
*
* @notapi
*/
void pwm_lld_disable_channel_notification(PWMDriver *pwmp,
pwmchannel_t channel) {
uint8_t i = timer_index(pwmp);
*regs_table[i].timsk &= ~(1 << (channel + 1));
}
/**
* @brief Disables the periodic activation edge notification.
* @pre The PWM unit must have been activated using @p pwmStart().
* @note If the notification is already disabled then the call has no effect.
*
* @param[in] pwmp pointer to a @p PWMDriver object
*
* @notapi
*/
void pwm_lld_disable_periodic_notification(PWMDriver *pwmp) {
uint8_t i = timer_index(pwmp);
*regs_table[i].timsk &= ~(1 << TOIE1);
}
/**
* @brief Deactivates the PWM peripheral.
*
* @param[in] pwmp pointer to the @p PWMDriver object
*
* @notapi
*/
void pwm_lld_stop(PWMDriver *pwmp)
{
uint8_t i = timer_index(pwmp);
*regs_table[i].tccrb &= ~((1 << CS12) | (1 << CS11) | (1 << CS10));
*regs_table[i].timsk = 0;
}
