mc68hc908gr8vp Freescale Semiconductor, Inc, mc68hc908gr8vp Datasheet - Page 24

• Manufacturer Part Number: mc68hc908gr8vp
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

General Description
1.5 Pin Functions
Descriptions of the pin functions are provided here.
1.5.1 Power Supply Pins (V
V
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
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.
1.5.2 Oscillator Pins (OSC1 and OSC2)
The OSC1 and OSC2 pins are the connections for the on-chip oscillator circuit. See
Generator Module
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 that is always activated, even when the reset pin is pulled low. See
Resets and
1.5.4 External Interrupt Pin (IRQ)
IRQ is an asynchronous external interrupt pin. This pin contains an internal pullup resistor that is always
activated, even when the reset pin is pulled low. See
1.5.5 CGM Power Supply Pins (V
V
Decoupling of these pins should be as per the digital supply. See
(CGMC).
24
DD
DDA
and V
and V
SS
SSA
Interrupts.
are the power supply and ground pins. The MCU operates from a single power supply.
are the power supply pins for the analog portion of the clock generator module (CGM).
(CGMC).
NOTE: Component values shown represent typical applications.
MC68HC908GR8 • MC68HC908GR4 Data Sheet, Rev. 7
DD
Figure 1-5. Power Supply Bypassing
and V
DDA
V
DD
SS
V
and V
DD
)
SSA
0.1 μF
MCU
+
C1
C2
Chapter 12 External Interrupt
)
V
Chapter 7 Clock Generator Module
SS
Freescale Semiconductor
(IRQ).
Chapter 7 Clock
Chapter 4
Figure 1-5