Are there any the limitations of using internal 1MHz oscillator to get highest Bus frequency (32MHz for S12ZVL)? On my board I am not able to go above 16 MHz bus Freq. With NXP's TRK-S12ZVL, I cannot go beyond 25MHZ. To me looks like some issue in the layout, but even with TRK-S12ZVL board (will surely be multi layer board) why not possible to achieve 32MHz Bus. Any special precautions?