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Shift Register Serial Communication. System Digital. D. D. D. D. Q. Q. Q. Q. Pokok Bahasan. Shift Registers Definisi Model I/O : Serial, Pararel dan Kombinasi Arah pergeseran : Kiri, Kanan dan dua arah Applikasi/penggunaan Implementasi VHDL MSI Shift Registers Komunikasi Serial. - PowerPoint PPT Presentation
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SHIFT REGISTERSERIAL COMMUNICATION
System Digital
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POKOK BAHASAN Shift Registers
Definisi Model I/O : Serial, Pararel dan Kombinasi Arah pergeseran : Kiri, Kanan dan dua arah Applikasi/penggunaan Implementasi VHDL
MSI Shift Registers Komunikasi Serial
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D QInput
Clock
D Q D Q D Q
Q3 Q2 Q1 Q0
Enable
Output
SHIFT REGISTERSMemanfaatkan register untuk penyimpanan, manipulasi dan transfer (pemindahan) data
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DEFINISI Register adalah sebuah rangkaian digital dengan
dua (2) fungsi utama : Data storage dan Data Movement Shift register menyediakan fungsi data movement A shift register “shifts” its output once every clock
cycle Shift register adalah sekelompok flip flop yang
dipasang secara linier dengan masukan dan keluaran saling disambungkan satu dengan yang lain, sehingga data akan digeser dari satu alat ke alat yang lain ketika rangkaian tersebut diaktifkan
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PEMANFAATAN SHIFT REGISTER
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Komunikasi UART -> Universal
asynchronous receiver/transmitter
Konversi antara serial dan pararel
Penyimpanan sementara di processor scratch-pad memories
Operasi Aritmatika Perkalian, pembagian
Applikasi counter Johnson counter ring counter LSFR counters
time delay devices more …
SHIFT REGISTER CHARACTERISTICS Tipe
Serial-in, Serial-out Serial-in, Parallel-out Parallel-in, Serial-out Parallel-in, Parallel-out Universal
Arah Left shift Right shift Rotate (right or left) Bidirectional
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n-bit shift register
DATA MOVEMENT Bit – bit dalam shift register dapat digeser
sesuai gambar dibawah ini
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n-bit shift register
n-bit shift register
DATA MOVEMENT Blok diagram shift register dengan berbagai
variasi input/output
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n-bit shift register
n-bit shift register
n-bit shift register
SERIAL-IN SERIAL-OUT Bit data masuk satu persatu
dan keluar satu per satu Satu flip flop bertugas
untuk menyimpan satu data Pergerakan data dapat
geser kiri / kanan, pada umumnya satu register hanya bisa satu arah.
Masukan Asynchronous preset dan clear digunakan untuk set nilai awal
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SERIAL-IN SERIAL-OUT Rangkaian logika ini menunjukkan gambar secara umum
Serial in Serial Out Shift Register Menggunakan SR Flip Flop Dirangkai sehingga memiliki perilaku seperti flip-flop D Nilai masukan input akan digeser ke setiap flip-flop
berpadanan dengan clock pulse
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N-Bit Shift Register
0N 1
SHIFT REGISTERS Shift register paling sederhana hanya menggunakan flip-flops Keluaran dari flip-flop disambungkan dengan masukan D pada flip-flop
berikutnya di sebelah kanan Setiap pulsa clock akan menggeser nilai register satu bit satu posisi ke
sebelah kanan Serial input (SI) menentukan status masukan Flipflop paling kiri pada saat
terjadinya pergeseran, Serial output (SO) diambil dari keluaran flipflop paling kanan
Perhatikan animasi
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Q Q QQ
SERIAL-IN SERIAL-OUT Cara paling mudah untuk
mempelajari adalah lihat ilustrasi pada sebelah kanan
4 bit data word “1011” akan di geser pada 4 bit shift register
One shift per clock pulse Data di tunjukkan masuk
dari sisi sebelah kiri dan keluar dari sisi kanan
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1
2
3
4
5
SERIAL-IN SERIAL-OUT Diagram di sebelah
kanan menunjukkan urutan 4 bit “1010” di load ke 4 bit SISO shift register
Setiap bit akan bergeser 1 posisi ke sebelah kanan pada setiap terjadi clock leading edge
dibutuhkan 4 pulsa clock untuk memasukkan seluruh bit ke register. 13
SERIAL-IN SERIAL-OUT Diagram disebelah
kanan menunjukkan urutan 4 bit “1010” unloaded dari 4 bit SISO shift register
Setiap bit akan bergerak satu bit ke kanan setiap signal clock
Dibutuhkan 4 clock untuk mengakhiri proses tersebut.
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SERIAL-IN SERIAL-OUT SISO di pergunakan
untuk komunikasi data : RS-232 modem transmission
and reception Ethernet links SONET etc.
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SERIAL-IN SERIAL-OUT IN VHDL Berikut ini adalah kode program implementasi VHDL untuk 8
bit shift register pada positif edge clock Serial in Serial Out
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library ieee;use ieee.std_logic_1164.all;
entity shift is port(C, SI : in std_logic; SO : out std_logic);end shift;
architecture archi of shift is signal tmp: std_logic_vector(7 downto 0); begin process (C) begin if (C'event and C='1') then for i in 0 to 6 loop tmp(i+1) = tmp(i); end loop; tmp(0) = SI; end if; end process; SO = tmp(7);end archi;
KONVERSI SERIAL-TO-PARALLEL Konversi serial ke pararel
dibutuhkan pada saat Misal setelah menerima
transmisi data secara serial Ilustrasi 4 bit serial in
pararel out Shift register di gambarkan di sebelah kanan
Output Q pada flipflop paling kanan juga dapat berfungsi sebagai serial out.
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n-bit shift register
SERIAL-TO-PARALLEL CONVERSION Digunakan serial in
pararel out shift register sepanjang N untuk mengubah N bit word dari serial ke pararel.
Di butuhkan pulsa N clock untuk load dan 1 clock pulse untuk unload
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SERIAL-TO-PARALLEL CONVERSION Dua buah shift
register di sebelah kanan digunakan konversi serial data ke pararel data
Register bagian bawah akan menyediakan untuk register bagian atas, ketika di geser oleh register bag bawah
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PARALLEL-TO-SERIAL CONVERSION Data di applikasikan ke bentuk
pararel, kemudian di umpan masukkan ke Pin A hingga D.
Kemudian dibaca secara sequential pada register 1 bit pada satu waktu dari PA ke PD setiap 1 siklus clock dalam bentuk serial
Satu pulsa clock untuk load Empat pulsa clock untuk unload
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n-bit shift register
PARALLEL-TO-SERIAL CONVERSION Logic circuit for a parallel-in, serial-out shift
register
21Mux-like
0
0
1
0
1
1
PARALLEL-IN PARALLEL-OUT Parallel-in Parallel-out Shift
Registers can serve as a temporary storage device or as a time delay device
The DATA is presented in a parallel format to the parallel input pins PA to PD and then shifted to the corresponding output pins QA to QD when the registers are clocked
One clock pulse to load One pulse to unload
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n-bit shift register
UNIVERSAL SHIFT REGISTER Universal shift register Can do any combination of
parallel and serial input/output operations
Requires additional inputs to specify desired function
Uses a Mux-like input gating
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L/SL/S
A
B
A
BF
1
01
0
UNIVERSAL SHIFT REGISTER Parallel-in, parallel-out shift register
24
Mux-like
0
0
1
0
1
1
UNIVERSAL SHIFT REGISTER Parallel shift register (can serve as converting
parallel-in to serial-out shifter):
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MSI SHIFT REGISTERS 74LS164 is an 8-Bit
Serial-In Parallel-Out Shift Register
Typical Shift Frequency of 35 MHz
Asynchronous Master Reset
Gated Serial Data Input
Fully Synchronous Data Transfers
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MSI SHIFT REGISTERS 74LS164 8-Bit Serial-In Parallel-Out Shift
Register
27
MSI SHIFT REGISTERS The 74LS164 is an edge-
triggered 8-bit shift register with serial data entry and an output from each of the eight stages.
Data is entered serially through one of two inputs (A or B); either of these inputs can be used
as an active HIGH Enable for data entry through the other input
an unused input must be tied HIGH, or both inputs connected together
28
MSI SHIFT REGISTERS Each LOW-to-HIGH transition on
the Clock (CP) input shifts data one place to the right
This also enters into Q0 the logical AND of the two data inputs (A•B) that existed before the rising clock edge.
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MSI SHIFT REGISTERS
74LS164 logic diagram
30
A LOW level on the Master Reset (MR) input overrides all other inputs and clears the register asynchronously, forcing all Q outputs LOW.
MSI SHIFT REGISTERS 74LS166 is an 8-Bit
Shift Register Parallel-in or serial-in
shift/load input establishes the parallel-in or serial-in mode
Serial-out Synchronous Load
Serial data flow is inhibited during parallel loading
Direct Overriding Clear
31
MSI SHIFT REGISTERS 74LS166 is an 8-Bit Shift Register
32
MSI SHIFT REGISTERS 74LS166 8-Bit Shift Register is a parallel-in or
serial-in, serial-out shift register
33
MSI SHIFT REGISTERS 74LS166 is an 8-Bit Shift
Register
34
MSI SHIFT REGISTERS 74LS166 is an 8-Bit Shift Register
35
MSI SHIFT REGISTERS 74LS194 4-Bit
Bidirectional Universal Shift Register
may be used in serial-serial, shift left, shift right, serial-parallel, parallel-serial, and parallel-parallel
data register transfers
36
MSI SHIFT REGISTERS 74LS194 4-Bit Bidirectional Universal Shift
Register
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MSI SHIFT REGISTERS 74LS194 control inputs S1 and S0
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MSI SHIFT REGISTERS 74LS194 4-Bit Bidirectional Universal Shift
Register
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01 11 10 00 01 11 10 0001 11 10 0001 11 10 00
MSI SHIFT REGISTERS 74LS194 4-Bit Bidirectional Universal Shift
Register
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“UNIVERSAL” SHIFT REGISTER74X194
Shift left Shift right Load Hold
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MSI SHIFT REGISTERS One stage of the 74x194
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VHDL DHIFT REGISTER Universal shift
register design
The 3-bit function select determines the operation of the register
Serial in and Parallel load available
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library IEEE;use IEEE.std_logic_1164.all;use IEEE.std_logic_unsigned.all;
entity Vshftreg is port (CLK, CLR, RIN, LIN: in STD_LOGIC; S: in STD_LOGIC_VECTOR (2 downto 0); -- function select D: in STD_LOGIC_VECTOR (7 downto 0); -- data in Q: out STD_LOGIC_VECTOR (7 downto 0) -- data out);end Vshftreg;
architecture Vshftreg_arch of Vshftreg issignal IQ: STD_LOGIC_VECTOR (7 downto 0);beginprocess (CLK, CLR, IQ) begin if (CLR='1') then IQ <= (others=>'0'); elsif (CLK'event and CLK='1') then case CONV_INTEGER(S) is when 0 => null; -- Hold when 1 => IQ <= D; -- Load when 2 => IQ <= RIN & IQ(7 downto 1); -- Shift right when 3 => IQ <= IQ(6 downto 0) & LIN; -- Shift left when 4 => IQ <= IQ(0) & IQ(7 downto 1); -- Shift circular right when 5 => IQ <= IQ(6 downto 0) & IQ(7); -- Shift circular left when 6 => IQ <= IQ(7) & IQ(7 downto 1); -- Shift arithmetic right when 7 => IQ <= IQ(6 downto 0) & '0'; -- Shift arithmetic left when others => null; end case; end if; Q <= IQ; end process;end Vshftreg_arch;
MSI SHIFT REGISTERS 74LS299 is an 8-bit
universal shift/storage register with 3-state outputs
Four modes of operation are possible: hold (store) shift left shift right load data
44
MSI SHIFT REGISTERS 74LS299 universal shift/storage register
45
MSI SHIFT REGISTERS 74LS299 universal shift/storage register
46
S0S1
D Q
CPCD
MSI SHIFT REGISTERS 74LS299 logic circuit diagram:
The parallel load inputs and flip-flop outputs are multiplexed to reduce the total number of package pins.
Separate outputs are provided for flip-flops Q0 and Q7 to allow easy cascading.
A separate active LOW Master Reset is used to reset the register.
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SERIAL COMMUNICATIONSA practical application of Registers / Shift Registers48
SERIAL DATA SYSTEMS (E.G., TPC)
Read discussion and study circuits in text. 49
SERIAL DATA TRANSMISSION Parallel-to-serial conversion for serial
transmission
50serial transmission media
in: parallel data
out: parallel data
Destination moduleSource module
SERIAL DATA IN THE PHONE SYSTEM (E-1) 2.048 Mb/s links between phone switches
and subscribers partitioned into 32 64 Kb/s channels
Each channel gets a timeslot in a “frame” where it can send 8 bits every 125 sec. 8000 frames/sec
51
TIMESLOT DETAILS
52
count = 255
PARALLEL-TO-SERIAL CONVERSION
53
256
LSBs are bit number
Assert shift-registerLOAD input during bit 7
Timeslot number canbe decoded and usedto select source ofparallel data
Serial data todestination
count = 255
SERIAL-TO-PARALLEL CONVERSION
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Synchronize destination’s counter to source’s
Shift in serial data
Detect that acomplete bytehas beenreceived
Holding registerfor completebyte
Note:loads0…0
DESTINATION TIMING
55Serial-in, parallel-outshift register outputs
Holding-register outputsGrab complete byte when available
SERIAL COMMUNICATION ON ONE WIRE Serial communication requires three signals:
CLOCK, SYNC, and DATA. Yet only one “wire” is used. How?
One solution: Manchester code.
56
• Or use a phase-locked loop (analog circuit)to extract clock from the data:
STILL A COUPLE OF PROBLEMS Framing -- SYNC signal
Solution: Use a unique data pattern for SYNC PLL clock recovery -- what if too many zeroes
are transmitted? PLL can’t stay in sync. Solution: Use a code that guarantees a minimum
number of ones Phone system: Map 00000000 --> 00000010
(creating slight voice distortion) Gigabit Ethernet: Uses 8B10B code, solving
both problems Map each byte into 8 bits Use only a “good” subset of 210 code words Use another code word for synchronization
57
ASSIGNMENTS Completed Part 2 Midterm problems due
Wednesday
Continue working on the MIPS project Description available on the course web page
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