MC9S12XD256MAL Datasheet, PDF (389/1348 Pages) Freescale Semiconductor, Inc – Freescale’s Scalable Controller Area Network

Chapter 8 Pulse-Width Modulator (S12PWM8B8CV1)
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%
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
389