Chapter 12 Pulse-Width Modulator (S12PWM8B8CV1)
MC9S12XDP512 Data Sheet, Rev. 2.11
Freescale Semiconductor 587
To calculate the output frequency in center aligned output mode for a particular channel, take the selected
clock source frequency for the channel (A, B, SA, or SB) and divide it by twice the value in the period
register for that channel.
PWMx Frequency = Clock (A, B, SA, or SB) / (2*PWMPERx)
PWMx Duty Cycle (high time as a% of period):
Polarity = 0 (PPOLx = 0)
Duty Cycle = [(PWMPERx-PWMDTYx)/PWMPERx] * 100%
Polarity = 1 (PPOLx = 1)
Duty Cycle = [PWMDTYx / PWMPERx] * 100%