mc68hc711k4 Freescale Semiconductor, Inc, mc68hc711k4 Datasheet - Page 36

• Manufacturer Part Number: mc68hc711k4
• Description: Hcmos Microcontroller Unit
• Manufacturer: Freescale Semiconductor, Inc

Pin Description
2.3 Power Supply (V
2.4 Reset (RESET)
Technical Data
36
The MCU operates from a single 5-volt (nominal) power supply. V
the positive power input and V
pairs of pins on the K series devices and two sets on the KS devices. All
devices contain a separate pair of power inputs, AV
analog-to-digital (A/D) converter, so that the A/D circuitry can be
bypassed independently.
Very fast signal transitions occur on the MCU pins. The short rise and fall
times place high, short duration current demands on the power supply.
To prevent noise problems, provide good power supply bypassing at the
MCU. Also, use bypass capacitors that have good high-frequency
characteristics and situate them as close to the MCU as possible.
Bypass requirements vary, depending on how heavily the MCU pins are
loaded.
This active-low, bidirectional control signal acts as an input to initialize
the MCU to a known start-up state. It also serves as an open-drain
output to indicate that an internal failure has been detected in either the
clock monitor or computer operating properly (COP) watchdog circuit.
The CPU distinguishes between internal and external reset conditions
by counting the number of E-clock cycles that occur between the start of
reset and the presence of a logic 1 voltage level on the reset pin. Less
than two cycles indicates an internal reset; greater than two, an external
reset. To prevent the device from misinterpreting the kind of reset that
occurs, do not connect an external resistor-capacitor (RC) power-up
delay circuit directly to the reset pin.
DD
Freescale Semiconductor, Inc.
For More Information On This Product,
, V
SS
, AV
Go to: www.freescale.com
DD
Pin Description
, and AV
SS
SS
)
is ground. There are three V
DD
and AV
M68HC11K Family
MOTOROLA
SS
DD
, for the
/V
DD
SS
is