HC705RC17GRSSLASHD datasheet(87/126 Pages) NXP

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Phase-Locked Loop (PLL) Synthesizer

Operation During Stop Mode

MC68HC705RC17 — Rev. 2.0

General Release Specification

Phase-Locked Loop (PLL) Synthesizer

NOTE:

For the MC68HC705RC17, the 4.194-MHz bus clock frequency should

not be selected. The 2.097-MHz bus clock frequency should not be

selected when running the part below VDD = 3.0 V.

10.4 Operation During Stop Mode

The PLL is switched to low-frequency bus rate and is turned off

temporarily when STOP is executed. Coming out of stop mode with an

external IRQ, the PLL is turned on with the same configuration it had

before going into STOP with the exception of BCS which is reset.

Otherwise, the PLL control register is in the reset condition.

10.5 Noise Immunity

The MCU should be insulated as much as possible from noise in the

system. These steps are recommend to help prevent problems due to

noise injection.

1. The application environment should be designed so that the MCU

is not near signal traces which switch often, such as a clock signal.

2. The oscillator circuit for the MCU should be placed as close as

possible to the OSC1 and OSC2 pins on the MCU.

3. To minimize noise, all power pins should be filtered by using

bypass capacitors placed as close as possible to the MCU.

See the application note

Designing for Electromagnetic Compatibility

(EMC) with HCMOS Microcontrollers, available through the Motorola

Literature Distribution Center, document number AN1050/D.

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

HC705RC17GRS/D Datasheet(PDF) 87 Page - NXP Semiconductors