Motorola Espresso Maker MC68340 사용자 설명서

MOTOROLA

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DATA BUS

MUX

D15–D0

ADDRESS BUS

IMB

INTERFACE

SIGNALS

I

N
T
E
R
N

A
L

B
U

S

DATA BUS

DATA

D7–D0

EXTERNAL

INTERFACE SIGNALS

X1

X2

SCLK

BAUD RATE

GENERATOR

LOGIC

CHANNEL B

FOUR-CHARACTER

RECEIVE BUFFER

TWO-CHARACTER

TRANSMIT BUFFER

RxDB

TxDB

RTSB

CTSB

CHANNEL A

FOUR-CHARACTER

RECEIVE BUFFER

TWO-CHARACTER

TRANSMIT BUFFER

RxDA

TxDA

RTSA

TxRDYA

CTSA

CONTROL

INTERNAL
CONTROL

LOGIC

S

E
R

I

A

L

M
O
D
U

L

E

RxRDYA

This input is one of two connections to a crystal or a single connection to an external
clock. A crystal or an external clock signal, at 3.6864 MHz, must be supplied when using
the baud rate generator. If a crystal is used, a capacitor of approximately 10 pF should be
connected from this signal to ground. If this input is not used, it must be connected to V

CC

or GND. Refer to Section 10 Applications for an example of a clock driver circuit.

This output is the additional connection to a crystal. If a crystal is used, a capacitor of
approximately 5 pF should be connected from this signal to ground. If an external TTL-
level clock is used on X1, the X2 output must be left open. Refer to Section 10
Applications for an example of a clock driver circuit.

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Freescale Semiconductor, Inc.

For More Information On This Product,

   Go to: www.freescale.com

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