Sonic Alert msm85c154hvs QHSHIFT/ Load Serial Clock, Inhibit F E D C B a Input, Rxd Px.X Txd

MSM80C154S/83C154S/85C154HVS

4.6.4Serial port application examples 4.6.4.1 I/O extension

I/O extension can be achieved by using the serial port in mode 0. An input extension example is shown in Figure 4-37 and the corresponding timing chart is shown in Figure 4-38. Following output of the latch pulse from PX.X, REN=“1” and R1=“0” are set for shift in of 74LS1 65 data.

VCC

QHSHIFT/ LOAD SERIAL IN

CLOCK	74LS165
INHIBIT	CK

H G F E D C B A

INPUT

MSM80C154S

MSM83C154S

RXD

PX.X

TXD

Figure 4-37 Input extension example

RX.X

TXD

74LS165-QH

Figure 4-38 Input extension example timing chart

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