MC68HC908GR16 Datasheet, PDF (24/310 Pages) Motorola, Inc – Microcontrollers

General Description
Freescale Semiconductor, Inc.
1.5 Pin Functions
Descriptions of the pin functions are provided here.
1.5.1 Power Supply Pins (V_DD and V_SS)
V_DD and V_SS are the power supply and ground pins. The MCU operates from a
single power supply.
Fast signal transitions on MCU pins place high, short-duration current demands on
the power supply. To prevent noise problems, take special care to provide power
supply bypassing at the MCU as Figure 1-4 shows. Place the C1 bypass capacitor
as close to the MCU as possible. Use a high-frequency-response ceramic
capacitor for C1. C2 is an optional bulk current bypass capacitor for use in
applications that require the port pins to source high current levels.
MCU
V_DD
V_SS
C1
0.1 µF
+
C2
V_DD
Note: Component values shown represent typical applications.
Figure 1-4. Power Supply Bypassing
1.5.2 Oscillator Pins (OSC1 and OSC2)
OSC1 and OSC2 are the connections for an external crystal, resonator, or clock
circuit. See Section 4. Clock Generator Module (CGM).
1.5.3 External Reset Pin (RST)
A logic 0 on the RST pin forces the MCU to a known startup state. RST is
bidirectional, allowing a reset of the entire system. It is driven low when any internal
reset source is asserted. This pin contains an internal pullup resistor. See
Section 15. System Integration Module (SIM).
Data Sheet
24
General Description
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Go to: www.freescale.com
MC68HC908GR16 — Rev. 1.0
MOTOROLA