MC9S12E64CFU Freescale Semiconductor, MC9S12E64CFU Datasheet - Page 403

• Manufacturer Part Number: MC9S12E64CFU
• Description: IC MCU 64K FLASH 25MHZ 80-QFP
• Manufacturer: Freescale Semiconductor
• Series: HCS12r

Specifications of MC9S12E64CFU

• Core Processor: HCS12
• Core Size: 16-Bit
• Speed: 25MHz
• Connectivity: EBI/EMI, I²C, SCI, SPI
• Peripherals: POR, PWM, WDT
• Number Of I /o: 60
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 2.35 V ~ 2.75 V
• Data Converters: A/D 16x10b; D/A 2x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-QFP
• Data Bus Width: 16 bit
• Data Ram Size: 4 KB
• Interface Type: SCI, SPI
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 60
• Number Of Timers: 16 bit
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit
• On-chip Dac: 8 bit, 2 Channel
• For Use With: M68EVB912E128 - BOARD EVAL FOR MC9S12E128/64
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: No RoHS Version Available

Chapter 12 Pulse-Width Modulator (PWM8B6CV1)
12.4
Functional Description
12.4.1
PWM Clock Select
There are four available clocks called clock A, clock B, clock SA (scaled A), and clock SB (scaled B).
These four clocks are based on the bus clock.
Clock A and B can be software selected to be 1, 1/2, 1/4, 1/8,..., 1/64, 1/128 times the bus clock. Clock SA
uses clock A as an input and divides it further with a reloadable counter. Similarly, clock SB uses clock B
as an input and divides it further with a reloadable counter. The rates available for clock SA are software
selectable to be clock A divided by 2, 4, 6, 8, ..., or 512 in increments of divide by 2. Similar rates are
available for clock SB. Each PWM channel has the capability of selecting one of two clocks, either the
pre-scaled clock (clock A or B) or the scaled clock (clock SA or SB).
The block diagram in
Figure 12-34
shows the four different clocks and how the scaled clocks are created.
12.4.1.1
Prescale
The input clock to the PWM prescaler is the bus clock. It can be disabled whenever the part is in freeze
mode by setting the PFRZ bit in the PWMCTL register. If this bit is set, whenever the MCU is in freeze
mode the input clock to the prescaler is disabled. This is useful for emulation in order to freeze the PWM.
The input clock can also be disabled when all six PWM channels are disabled (PWME5–PWME0 = 0)
This is useful for reducing power by disabling the prescale counter.
Clock A and clock B are scaled values of the input clock. The value is software selectable for both clock A
and clock B and has options of 1, 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, or 1/128 times the bus clock. The value
selected for clock A is determined by the PCKA2, PCKA1, and PCKA0 bits in the PWMPRCLK register.
The value selected for clock B is determined by the PCKB2, PCKB1, and PCKB0 bits also in the
PWMPRCLK register.
MC9S12E128 Data Sheet, Rev. 1.07
Freescale Semiconductor
403