MC9S12P32MFT Freescale Semiconductor, MC9S12P32MFT Datasheet - Page 359

• Manufacturer Part Number: MC9S12P32MFT
• Description: 16-bit Microcontrollers - MCU 16 BIT 32K FLASH
• Manufacturer: Freescale Semiconductor

Specifications of MC9S12P32MFT

• Rohs: yes
• Core: S12
• Processor Series: MC9S12P
• Data Bus Width: 16 bit
• Maximum Clock Frequency: 32 MHz
• Program Memory Size: 32 KB
• Data Ram Size: 4 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 3.13 V to 5.5 V
• Operating Temperature Range: - 40 C to + 125 C
• Package / Case: QFN-48
• Mounting Style: SMD/SMT

10.4.2.6
For center aligned output mode selection, set the CAEx bit (CAEx = 1) in the PWMCAE register and the
corresponding PWM output will be center aligned.
The 8-bit counter operates as an up/down counter in this mode and is set to up whenever the counter is
equal to 0x0000. The counter compares to two registers, a duty register and a period register as shown in
the block diagram in
changes state causing the PWM waveform to also change state. A match between the PWM counter and
the period register changes the counter direction from an up-count to a down-count. When the PWM
counter decrements and matches the duty register again, the output flip-flop changes state causing the
PWM output to also change state. When the PWM counter decrements and reaches 0, the counter direction
changes from a down-count back to an up-count and a load from the double buffer period and duty
registers to the associated registers is performed as described in
Duty.”
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.
Freescale Semiconductor
•
The counter counts from 0 up to the value in the period register and then back down to 0. Thus the
PWMx frequency = clock (A, B, SA, or SB) / (2*PWMPERx)
PPOLx = 0
PPOLx = 1
Center Aligned Outputs
Changing the PWM output mode from left aligned output 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.
Figure
E = 100 ns
Figure 10-37. PWM Left Aligned Output Example Waveform
Figure 10-38. PWM Center Aligned Output Waveform
10-35. When the PWM counter matches the duty register the output flip-flop
PWMDTYx
S12P-Family Reference Manual, Rev. 1.13
PWMPERx
PERIOD = 400 ns
DUTY CYCLE = 75%
NOTE
Period = PWMPERx*2
Pulse-Width Modulator (PWM8B6CV1) Block Description
Section 10.4.2.3, “PWM Period and
PWMPERx
PWMDTYx
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