Справочник Пользователя для Motorola MC68HC908MR16
General Description
Pin Assignments
MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
Advance Information
MOTOROLA
General Description
35
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
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.
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.
Figure 1-4. Power Supply Bypassing
1.5.2 Oscillator Pins (OSC1 and OSC2)
The OSC1 and OSC2 pins are the connections for the on-chip oscillator
circuit. For more detailed information, see
circuit. For more detailed information, see
.
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
is bidirectional, allowing a reset of the entire system. It is driven low when
MCU
V
DD
C2
C1
0.1
µ
F
V
SS
V
DD
+
Note: Component values shown represent typical applications.
1–10
µ
F