PWM_REG_PRESCAL
if ((PWM_REG_PRESCAL(val, pwm->hwpwm) == PWM_PRESCAL_MASK) &&
prescaler = prescaler_table[PWM_REG_PRESCAL(val, pwm->hwpwm)];
if (PWM_REG_PRESCAL(ctrl, pwm->hwpwm) != prescaler) {