Test: Serial Communication Unit - Computer Science Engineering (CSE) MCQ

The serial communication requires less number of conductors and thus it is cheaper. It is slow as the bits are transmitted one by one along with start, stop and parity bits.

Serial communication is more popular for communication over longer distances as it requires less number of conductors.

The mcs 51 architecture supports simultaneous transmission and reception of binary data byte by byte i.e. full duplex mode of communication. It supports serial transmission and reception of data using standard serial communication interface and baud rates.

 Here, baud rate can be defined as the number of bits transmitted or received per second.

the serial communication unit consists of transmission unit and reception unit. The task of converting the byte into serial form and transmitting it bit by bit along with start, stop and parity bits is carried out by transmission unit.

once a byte for transmission is written to the serial buffer(SBUF) register, the transmission unit does not require assistance from processor.

The transmission unit and receiver unit both are controlled by using a common SCON(Serial Port Control) Register. Also both units share a common serial buffer(SBUF) register which is a common 8-bit serial data interface.

During serial reception, the receive buffer 1 receives serial bits and converts to a byte, it then transfers the received parallel byte in receive buffer 2.

 If SM0=1, SM1=0, then the 9-bit asynchronous transceiver is selected.

The bit, SM2 is set if the microcontroller is expected to communicate in multiprocessor system.