AVR Microcontroller test on “I2C Protocol”.
1. Which of the following is correct?
a) I2C is a technique by which data is transmitted with the help of only eight pins
b) SDA is used to synchronize data transfer between two chips
c) TWI is another name for I2C
d) All of the mentioned
Answer: c
Clarification: I2C is a technique by which data is transmitted between two devices by the help of only 2 pins so it is also called Two wire Serial Interface.
2. Which of the following is true about the I2C protocols?
a) the data line cannot change when the clock line is high
b) the data line can change when the clock line is high
c) the clock line cannot change when the data line is high
d) the clock line can change when the data line is high
Answer: a
Clarification: According to I2C protocols, the data line(SDA) changes only if the clock line(SCL) is at its active low level.
3. I2C is a connection oriented communication protocol.
a) true
b) false
c) cant be said
d) depends on the conditions
Answer: a
Clarification: I2C is a connection oriented protocol i.e each transmission is initiated by a START condition and is terminated by a STOP condition.
4. The STOP condition is generated by a
a) high to low change in the SDA line when the SCL is low
b) high to low change in the SDA line when the SCL is high
c) low to high change in the SDA line when the SCL is low
d) low to high change in the SDA line when the SCL is high
Answer: c
Clarification: The STOP condition is generated when there is a low to high change in the SDA line when the SCL is low.
5. For receiving the acknowledgment
a) SDA from the transmitter should be high
b) SDA from the transmitter should be low
c) SDA from receiver should be high
d) SDA from receiver should be low
Answer: d
Clarification: The packet format in I2C consists of 9 bits, out of which first 8 are the data bits while the ninth bit is the acknowledgment bit. For obtaining the acknowledgment, the SDA line of the receiver should be pushed to low.
6. What steps are followed to complete the data transfer?
a) START condition, STOP condition
b) Address packet
c) One or more data packet
d) All of the mentioned
Answer: d
Clarification: For having the complete data transfer, the steps that are actually being followed are START condition, address packet, one or more data packet, STOP condition.
7. I2C is ideal for short distances?
a) true
b) false
c) cant be said
d) depends on the conditions
Answer: a
Clarification: I2C is that module of the AVR, which is used for short distances.
8. Which of the following is a register used for programming AVR’s I2C module?
a) TWBR
b) TWCR
c) TWSR
d) All of the mentioned
Answer: d
Clarification: TWBR( TWI Bit rate register), TWCR( TWI Control Register), TWSR(TWI Status Register), TWAR(TWI Address Register), TWDR( TWI Data Register) are used for programming an AVR’s I2C module.
9. Which bit is polled to know that whether the TWI is ready or not?
a) TWWC
b) TWINT
c) TWEA
d) All of the mentioned
Answer: b
Clarification: TWINT is the bit that is polled to know that whether the TWI is ready or not.
10. Is status flag important in multi master systems?
a) yes
b) no
c) depends on the conditions
d) cant be said
Answer:a
Clarification: Yes, the status flag plays a very vital role in multi master systems.