Ch 13 : Shift RegistersCh. 13 : Shift Registers

OutlineOutlineShift Register BasicsgParallel to Serial ConversionRe-circulating RegisterSerial to Parallel ConversionRing- and Johnson-shift counterh fShift register IC’s

System Design applications Driving a stepping motor

Three state Buffers, Latches and Transceivers

Ch. 13: Shift Registers 2

IntroductionIntroduction

Registers required in digital systems for the temporary storage of a group of bitsData bits (1’s and 0’s) traveling through a digital system sometimes have to be temporary stopped, copied, moved, or even shifted to the right or left one or more positionsA shift register facilities this movement and storage of data bits

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1 Shift Register Basics1. Shift Register Basics

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2. Parallel to Serial Conversion

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3 Re circulating Register3. Re-circulating Register

Re-circulating the rightmost data bits back into the beginning of the register can be g g gaccomplished by connecting Q0 back to J3and 0 back to K3Q0 3Q

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4 Serial to Parallel Conversion4. Serial to Parallel Conversion

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5. Ring- and Johnson-shift gcounter

Two common circuits that are used to create sequential control waveforms qThey are similar to a synchronous counter

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Ring shift counterg

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Johnson shift counter

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6 Shift register IC’s6. Shift register IC s

74164: 8 bit serial-in parallel-out register74165: 8 bit serial or parallel in, serial-out 74165: 8 bit serial or parallel in, serial out shift register74194: bidirectional universal shift register74194: bidirectional universal shift register

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Three state outputsThree state outputsThe output can have one of three levels: HIGH LOW or The output can have one of three levels: HIGH, LOW or Float (High Impedance)In float state the output is neither HIGH or LOW and pcannot sink nor source current

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7 System Design applications7. System Design applicationsTraffic light controller that goes through Traffic light controller that goes through the following sequence:

• Green 20 sGreen, 20 s• Yellow, 10 s• Red, 20s

Also at night, flash the yellow light on and off continuouslyff n n y

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8 Driving a stepping motor8. Driving a stepping motor

p

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9. Three state Buffers, Latches and Transceivers

p

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ProjectsProjects

Jam (24 jam, 60 mnt) dengan setting jamLampu LL 15,5,15 pada 5am-6pmLampu LL 15,5,15 pada 5am 6pmLampu LL 8,2,8 pada 7-19Ti t d 7 59 b h L LL Timer count down 7.59 merubah Lampu LL hanya kuning

hTimer count up 3.33 merubah Lampu LL hanya kuning

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