MM912H634CV1AE Freescale Semiconductor, MM912H634CV1AE Datasheet - Page 98

• Manufacturer Part Number: MM912H634CV1AE
• Description: 64KS12 LIN2xLS/HS Isense
• Manufacturer: Freescale Semiconductor
• Series: -r

Specifications of MM912H634CV1AE

• Applications: Automotive
• Core Processor: HCS12
• Program Memory Type: FLASH (64 kB)
• Controller Series: HCS12
• Ram Size: 6K x 8
• Interface: LIN
• Number Of I /o: -
• Voltage - Supply: 5.5 V ~ 27 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP Exposed Pad
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

in
down to 0. Thus the effective period is PWMPERx*2.
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.
As an example of a center aligned output, consider the following case:
Figure 28
4.14.4.2.7
Table 131
Freescale Semiconductor
Section 4.14.4.2.3, “PWM Period and
•
•
E = 100 µs
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%
Clock Source = E, where E = 10 kHz (100 µs period)
PWMx Frequency = 10 kHz/8 = 1.25 kHz
PWMx Period = 800 µs
PWMx Duty Cycle = 3/4 *100% = 75%
shows the output waveform generated.
summarizes the boundary conditions for the PWM, regardless of the output mode (left aligned or center aligned).
PPOLx = 0
PPOLx = 1
PPOLx = 0
PWMPERx = 4
PWMDTYx = 1
Changing the PWM output mode from left aligned to center aligned output (or vice versa)
while channels are operating can cause irregularities in the PWM output. It is recommended
to program the output mode before enabling the PWM channel.
PWM Boundary Cases
Figure 28. PWM Center Aligned Output Example Waveform
PWMDTYx
Figure 27. PWM Center Aligned Output Waveform
Duty”. The counter counts from 0 up to the value in the period register and then back
MM912_634 Advance Information, Rev. 4.0
PWMPERx
DUTY CYCLE = 75%
PERIOD = 800 µs
Period = PWMPERx*2
NOTE
PWMPERx
PWM Control Module (PWM8B2C)
PWMDTYx
E = 100 µs
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