MC912DG128ACPV Freescale Semiconductor, MC912DG128ACPV Datasheet - Page 196

• Manufacturer Part Number: MC912DG128ACPV
• Description: IC MCU 128K FLASH 8MHZ 112-LQFP
• Manufacturer: Freescale Semiconductor
• Series: HC12r

Specifications of MC912DG128ACPV

• Core Processor: CPU12
• Core Size: 16-Bit
• Speed: 8MHz
• Connectivity: CAN, I²C, SCI, SPI
• Peripherals: POR, PWM, WDT
• Number Of I /o: 69
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 16x8/10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 112-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Oscillator
13.3.2 MC68HC912DT128A Oscillator Design Guidelines
Technical Data
196
NOTE:
Proper and robust operation of the oscillator circuit requires excellent
board layout design practice. Poor layout of the application board can
contribute to EMC susceptibility, noise generation, slow starting
oscillators, and reaction to noise on the clock input buffer. In addition to
published errata for the MC68HC912DT128A, the following guidelines
must be followed or failure in operation may occur.
An increase in the EXTAL–XTAL parasitic as a result of reducing
EXTAL–VSS parasitic is acceptable provided component value is
reduced by the appropriate value.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Minimize Capacitance to VSS on EXTAL pin — The Colpitts
oscillator architecture is sensitive to capacitance in parallel with
the resonator (from EXTAL to VSS). Follow these techniques:
Shield all oscillator components from all noisy traces (while
observing above guideline).
Keep the VSSPLL pin and the VSS reference to the oscillator
as identical as possible. Impedance between these signals must
be minimum.
Observe best practice supply bypassing on all MCU power
pins. The oscillator’s supply reference is VDD, not VDPLL.
Account for XTAL–VSS and EXTAL–XTAL parasitics in
component values.
Minimize XTAL and EXTAL routing lengths to reduce EMC
issues.
iii. Where possible, use XTAL as a shield between EXTAL
iv. Keep EXTAL capacitance to less than 1pF (2pF
ii. Observe a minimum spacing from the EXTAL trace to
i. Remove ground plane from all layers around resonator
Go to: www.freescale.com
and EXTAL route
all other traces of at least three times the design rule
minimum (until the microcontroller’s pin pitch prohibits
this guideline)
and VSS
absolute maximum)
Oscillator
MC68HC912DT128A — Rev 4.0
MOTOROLA