Embedded System Peripheral MCQ Quiz – Objective Question with Answer for Embedded System Peripheral

The three hardware signals are START, STOP and ACKNOWLEDGE. These signals help in the transmission of data between the slave and the masters.

The START signal is performed by the master by making the SCL and SDA pin high.

The START signal and ACKNOWLEDGE signals are almost similar but there exhibit a small change. The START signal is initiated by the master only but the ACKNOWLEDGE signal is a handshake between both the master and slave.

The data is transmitted in packets having one or more bytes. These packets of data are also known as a telegram.

The slave selection is performed by using the first byte as an address byte. When the address byte is sent out all the slave devices compare the address by its own value. If there is a match, the ACKNOWLEDGE signal will be sent by the slave.

The address value helps the master to select the device and indicates what operation should be taken. If the 8th bit is logic one, the read operation takes out and if it is logic zero, the write operation takes out.

For providing more addressing, an extended address is developed which possesses two bytes in which the first byte uses a special code to distinguish it from a single byte address so that the single-byte and double-byte address slaves can use a shared bus.

The peripheral having a small number of locations can use an auto-incrementing counter for accessing the next register. But this will not be applicable to bigger memory devices.

A combined format is an efficient method for the EEPROM because it is having a large number of registers.

The EEPROM is having a large number of registers, so the auto-incrementing counter will not be applicable. So there is an alternative method that uses an index value that is written to the chip, before accessing the data. This is called combined format and this combined format uses two data transfers. One is to write the data and the other is to read.

The peripherals which have a small number of locations can use an auto-increment counter within the peripheral in which each access selects the next register.

The polling can be used along with the counter to determine the timeout value.

The timeout value can be changed by the peripheral devices, so for a sophisticated system, a combination of polling and timer is used to check for the signal n times within a predefined interval. This can avoid the bus lock.

The collision detection technique helps to determine whether two or more masters are using the same bus in a multi-master device.

By using the bidirectional ports, each master can monitor the line and confirm its expected state and if it is not matched, a mismatch or collision had occurred which will discontinue the transmission by the master.