MC912DG128AMPVE Freescale Semiconductor, MC912DG128AMPVE Datasheet - Page 217

• Manufacturer Part Number: MC912DG128AMPVE
• Description: IC MCU 128K FLASH 8MHZ 112-LQFP
• Manufacturer: Freescale Semiconductor
• Series: HC12r

Specifications of MC912DG128AMPVE

• 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 ~ 125°C
• Package / Case: 112-LQFP
• Processor Series: HC912D
• Core: HC12
• Data Bus Width: 16 bit
• Data Ram Size: 8 KB
• Interface Type: CAN/I2C/SCI/SPI
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 69
• Number Of Timers: 8
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWHCS12
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 2 (8-ch x 10-bit)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

13.5.2 MC68HC912Dx128P Oscillator Circuit Specifications
13.5.2.1 Negative Resistance Margin
MC68HC912DT128A — Rev 4.0
MOTOROLA
Negative Resistance Margin (NRM) is a figure of merit commonly used
to qualify an oscillator circuit with a given resonator. NRM is an indicator
of how much additional resistance in series with the resonator is
tolerable while still maintaining oscillation. This figure is usually expected
to be a multiple of the nominal "maximum" rated ESR of the resonator to
allow for variation and degradation of the resonator.
Currently, many systems are optimized for NRM by adjusting the load
capacitors until NRM is maximized. This method may not achieve the
best overall NRM because the optimization method is empirical and not
analytical. That is, the method only achieves the best NRM for the
particular sample set of microcontrollers, resonators, and board values
tested. The figure below shows the anticipated NRM for a nominal 4MHz
resonator given the expected process variance of the microcontroller
(D60A), board, and crystal (excluding ESR). In this case, the value of
load capacitors providing the optimum NRM for a best-case situation
yield an unacceptable NRM for a worst-case situation (the slope of the
NRM vs. capacitance curve is very steep, indicating severe sensitivity to
small variations). If the NRM optimization happened to be performed on
a best-case sample set, there could be unexpected sensitivity at worst-
case.
Freescale Semiconductor, Inc.
For More Information On This Product,
8
10
Go to: www.freescale.com
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Negative Resistance Margin vs. Capacitance
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Oscillator
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Capacitance
22
27
MC68HC912Dx128P Pierce Oscillator Specification
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39
47
56
68
1000
100
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Technical Data
WCS
TYP
TYP
BCS
Oscillator
217