Synchronous & Asynchronous data transmission

Synchronous & Asynchronous data transmission for under graduation engineering student

1. Computer Peripherals & Interfacing Topic: Synchronous & Asynchronous data transmission

2. This is a data transmission method, in which a continuous stream of data signals is accompanied by timing signals to ensure that the receiver and transmitter in a step with one another. This used to describe continuous data transfer. So this transfers large amount of data one location to another . Synchronous Syn Syn data data data data data Data flow This id lower overhead thus, great throughput. But it is slightly more complex and this hardware is much expensive.

3. Simplified synchronous block data format syn syn syn Finish Start 8bit to each character Data

4. Synchronous serial interface Transmit data buffer register Receive data buffer register Status register Control register Control logic To data bus Chip enable - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Clock Clock Shift register Shift register Syn generator Syn recognition Transmitted serial data Register serial data

5. This is used to describe the process where the transmitted data encoded with start and stop beat, specifying the beginning and the ending of each character. Asynchronous It is cheaper than synchronous but this process is slow. 1 1 1 1 1 Start bit Stop bit

6. Asynchronous character format Idle State of line 1 Start bit 5 to 8 data bits Odd or even parity or unused 1 to 2 bit times Stop elements Remain idle or next start bit P bit

7. Asynchronous serial interface Transmit data buffer register Divide by sixteen Receive data buffer register Divide by sixteen Status register Control register Control logic - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Shift register Shift register Start bit Start bit Parity & stop bit Parity & stop bit To data bus External transmit clock External receive clock clock chip enable Transmitted serial data Register serial data Serial out Serial bus

8. Sends blocks or frames of data Fast transmission Needs a common clock signal, or some way to sharing it May have to wait briefly until data can be send Synchronous Asynchronous Sends one byte or character Slower transmission due to extra bits and gaps Cheap and easy to implement, no clock shearing Can transmit when ready

9. Prepared by: Ankon Gopal Banik Front End Developer | WWF (Web With Friends) m:  [phone] p:  027730402 e:  [email protected] 75-B, Kyetpara , Dhamrai , Dhaka, Bangladesh www.wwfriends.org

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