9 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification, and TI

does not warrant its accuracy or completeness. TI’s customers are responsible for determining

suitability of components for their purposes. Customers should validate and test their design

implementation to confirm system functionality.

9.1 Application Information

In this application, the SN74HCS164 is used to control seven-segment displays. Unlike other I/O expanders, the

SN74HCS164 does not need a communication interface for control. It can be easily operated with simple GPIO

pins. Additional control is provided with two serial inputs that feed into an AND gate.

At power-up, the initial state of the shift registers is unknown. To give them a defined state, the shift register

needs to be cleared. An RC can be connected to the CLR pin as shown in Typical Application Block Diagram to

initialize the shift register to all zeros.

9.2 Typical Application

Seven Segment

CLR

g

f

a

b

DP

c

d

e

a

b

c

d

e

f

g

DP

GND

A

B

CLK

MCU

R1

C1

Figure 9-1. Typical application block diagram

9.2.1 Design Requirements

9.2.1.1 Power Considerations

Ensure the desired supply voltage is within the range specified in the Recommended Operating Conditions. The

supply voltage sets the device's electrical characteristics as described in the Electrical Characteristics.

The positive voltage supply must be capable of sourcing current equal to the total current to be sourced by all

any transient current required for switching. The logic device can only source as much current as is provided by

Maximum Ratings.

The ground must be capable of sinking current equal to the total current to be sunk by all outputs of the

current required for switching. The logic device can only sink as much current as can be sunk into its ground

connection. Be sure not to exceed the maximum total current through GND listed in the Absolute Maximum

Ratings.

SN74HCS164

SCLS827 – AUGUST 2020

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