Saarada Institute 0f Technology and ScienceKhammam

(Approved by AICTE, Govt. of A.P& Affiliated to JNTUH)

Department of electronics and communication engineering

Presented by N.veeru

D.Veerababu A.Durgaprasad

A.samba

Guided byMr .B.Sanjai prasad M.tech

UART TRANSMITTER

AgendaAbstract IntroductionPrevious systemPresent system Required tools Block diagramApplication conclusionReference

Abstract…

Serial communication is a very useful feature in any project that you like to design.

Serial means that you can send multiple bits of data over a SINGLE line.1 line can send many bits.

This reduces the complexity of a design If you want to communicate to a computer, FPGA,

another device like a microcontroller or even interface to a digital to analog converter.

Introduction….. In the year 1980

Uart is introduced by mc gram hill Berkeley California U.S.A

A universal asynchronous receiver/transmitter, abbreviated UART

A piece of computer hardware that translates data between parallel and serial

UART is the micro chip

Commonly used in conjunction with communication standards such as RS-232, RS-422, RS-485 .

The uart take bytes of a data and transmits the individual bits in a sequential fashion at the destination.

A second uart re-assembles the bits into complete bytes .

A shift register which is the fundamental method of conversion between serial and parallel forms.

Previous system….

A uart is a usually an individual IC used for serial communication over a computer

This is serial communication this is the one

of the draw back

Why use a UART? A UART may be used High speed is required

An inexpensive communication link between two devices is required

UART communication is cheap

Differences….

Synchronous• It is a direct communication,

ware the communication are time synchronized.

• It will have frame this frame will consists of large amount of data.

Asynchronous• It is an indirect

communication.• It requires start and stop

bits for which large amount of space is waste.

Present system…..PC serial port is a UART!

Serializes data to be sent over serial cable De-serializes received data

SerialCable

SerialCable

Device

SerialPort

SerialPort

Transmitter

Transmission operation is simpler since it is under the control of the transmitting system.

the UART hardware generates a start bit, shifts the required number of data bits.

Since transmission of a single character may take a long time relative to CPU speeds.

Since full-duplex operation requires sent and received at the same time.

UART Transmission Example

Send the ASCII letter ‘W’ (1010111)

1

Line idling Start bit Parity bit(odd parity) Stop bit

Line idling again

Mark

Space

7 data bits – Least significant bit first

1 1 0 1 0 1 0

The Shift Register

Make it a 9-bit register. Have it load ‘0’ for the start bit on the right (LSB). Have it load 7 data bits in the middle. Have it load the parity bit on the left (MSB). Have it shift ‘1’ into the left so a stop bit is sent at the end. When it resets. Have it load all 1’s so that its default output is a ‘1’ (line idle

value)

P D6 D5 D4 D3 D2 D1 D0 ‘0’ Dout‘1’

Shift Register

‘0’

ReceiverAll operations of the UART hardware are controlled by a clock signal

The receiver tests the state of the incoming signal on each clock pulse, looking for the beginning of the start bit.

If the apparent start bit lasts at least one-half of the bit time,

Inserted between the receiver and shift register and host system interface

Block diagram

FIFO transmitter it’s transmit the bits one by one

FIFO receiver it’s receive the bits in normal mode

Register control is a temporary device , transmit and receive data from the cpu

7-bit Parity Generator in Verilog

module parity_gen (data, oddeven, parity); input [6:0] data; input oddeven; output parity;

assign parity = (^data) ^ oddeven;end module

Reduction XOR operator

Differences b/w VHDL & Verilog

VHDL• It is similar to

Ada(soft ware discription language)

• It is difficult to learn than verilog

VERILOG• It is similar to the c-

language.• It is easy to learn

than VHDL

A Uart usually contains the following components

Clock generator usually a multiple of the bit

Input and output register

Transmit and receive control

Read and write control logic

Transmit and receive buffer

Parallel data bus buffer

FIFO buffer memory

Features Dual channel version.

Advanced CMOS low power technology .

Programmable serial interface characteristics for each channel.

16 byte FIFO for receiver as well as for transmiter.

ApplicationTransmitting and receiving UARTs must be set for the same bit speed, character length, parity, and stop bits for proper operation.

The receiving Some very low-cost Since the CPU timing was critical

Home computers or embedded systems dispensed with a uart

Higher data throughput

Larger FIFO’s

Automatic flow controllers

TOOLS…

• SOFT WARES Xilinx.Mentor graphic tools(model sim).Micro wind.

CONCLUSION

• Serial communication is need for long distance And chief than the parallel communication

• Parallel communication is used for small distance , so we are prefering serial communication.

• SO serial communication is very usefull in future.

References

Google searchA.K.Ray

Any queries.“?”

Th

ank

“Q”