MC68HC11G5 Datasheet, PDF (24/195 Pages) Motorola, Inc – High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcontroller

Freescale Semiconductor, Inc.
2.2.2 Reset (RESET)
This active low bidirectional control signal pin is used as an input to initialize the MC68HC11G5 to
a known start-up state, and as an open-drain output to indicate an internal computer operating
properly (COP) watchdog circuit or clock monitor failure. This reset signal is significantly different
from the reset signal used on other Freescale MCUs. Refer to SECTION 5: RESETS, INTERRUPTS
AND LOW POWER MODES before designing circuitry to generate or monitor this signal.
MCU
EXTAL
XTAL
4xE
CMOS Compatible
External Oscillator
NC or
10k – 100
Load
Figure 2-1. Oscillator circuits: (a) External oscillator connections
First MCU
EXTAL
10M
XTAL
4xE
Crystal
25 pF*
25 pF*
220 ^{Second MCU}
EXTAL
NC or ^XTAL
10k – 100k
Load
* This value contains all stray capacitance
Figure 2-1. Oscillator circuits: (b) One crystal driving two MCUs
First MCU
EXTAL
10M
XTAL
4xE
Crystal
25 pF*
25 pF*
* This value contains all stray capacitance
Figure 2-1. Oscillator circuits: (c) Common crystal connections
OPERATING MODES AND SIGNAL DESCRIPTION
2-6
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