S912XET256J2VAGR Freescale Semiconductor, S912XET256J2VAGR Datasheet - Page 715

• Manufacturer Part Number: S912XET256J2VAGR
• Description: 16-bit Microcontrollers - MCU Watchdog OSC/Timer -40 C to + 105 C HCS12X MCU SPI
• Manufacturer: Freescale Semiconductor

Specifications of S912XET256J2VAGR

• Core: HCS12X
• Data Bus Width: 16 bit
• Maximum Clock Frequency: 50 MHz
• Program Memory Size: 256 KB
• Data Ram Size: 16 KB
• On-chip Adc: Yes
• Package / Case: LQFP
• Mounting Style: SMD/SMT
• A/d Bit Size: 12 bit
• A/d Channels Available: 24
• Interface Type: CAN, SCI, SPI
• Maximum Operating Temperature: + 105 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 119
• Number Of Timers: 25
• Program Memory Type: Flash
• Supply Voltage - Max: 1.98 V, 2.9 V, 5.5 V
• Supply Voltage - Min: 1.72 V, 2.7 V, 3.13 V

To calculate the output frequency in left 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 the value in the period register
for that channel.
As an example of a left aligned output, consider the following case:
The output waveform generated is shown in
Freescale Semiconductor
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•
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Duty Cycle = [PWMDTYx / PWMPERx] * 100%
PWMx Frequency = Clock (A, B, SA, or SB) / PWMPERx
PWMx Duty Cycle (high time as a% of period):
— Polarity = 0 (PPOLx = 0)
Duty Cycle = [(PWMPERx-PWMDTYx)/PWMPERx] * 100%
— Polarity = 1 (PPOLx = 1)
Clock Source = E, where E = 10 MHz (100 ns period)
PWMx Frequency = 10 MHz/4 = 2.5 MHz
PWMx Period = 400 ns
PWMx Duty Cycle = 3/4 *100% = 75%
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.
PPOLx = 0
PPOLx = 1
Figure 19-20. PWM Left Aligned Output Waveform
MC9S12XE-Family Reference Manual Rev. 1.25
PWMDTYx
Figure
NOTE
Period = PWMPERx
19-21.
Chapter 19 Pulse-Width Modulator (S12PWM8B8CV1)
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