I'm trying to move a small application from an S12 to an S12X and I'm having a few problems. First of all I want it to run at 40MHz bus speed so I've set the PLL to 80MHz compared to the S12 which used to run from a 16MHz crystal without PLL. From here the problems started... I tried to set the RTI interval at 512us (0x44) and I don't know if that's correct or if it's working. Next I'm having problems with the timer prescaler. How do I set the prescaler for 1us ? And last, I've noticed that the PWM is acting a little weird. I have a buzzer on my board and i set the pwm frequency to 1953 Hz on both MCUs. However, on the S12 I can hear the buzzer very loud compared to the S12X at the same volume setting. And the volume goes lower as i increase the PLL freq. or higher as i decrease it. The same happends with a motor which is controlled by the MCU. On the S12 i get a lot of power from the motor and on the S12X it is running very "soft".
Any help is greatly appreciated.