IOT Multiple Choice Questions on “I2C Protocol”.
1. Two wire interface is also called as _________
a) UART
b) SPI
c) I2C
d) USART
Answer: c
Clarification: The i2c protocol also known as the two wire interface is a simple serial communication protocol that uses just pins of a microcontroller namely SCL and SDA.
2. I2c will address large number of slave devices.
a) True
b) False
Answer: a
Clarification: This protocol will address a large number of slave devices that are connected to the same bus.
3. SDA is having a ____________transition when the clock line SCL is high.
a) high to low
b) low to high
c) low to low
d) high to high
Answer: a
Clarification: SDA is having a high to low transition when the clock line SCL is high. Under normal circumstances this does not happen as you can see in the subsequent clock pulses that the data line is stable in one state, either high or low when the clock line is high.
4. Inter Integrated Circuit is a _____________
a) Single master, single slave
b) Multi master, single slave
c) Single master, multi slave
d) Multi master, multi slave
Answer: d
Clarification: I2C pronounced as I-squared-C, is a multi master, multi salve. It is typically used for attaching lower-speed peripheral IC’s to processors and micro controllers in short distance, intra band communication.
5. Typical voltages used are ___________
a) 5v
b) 3.3v
c) 5v or 3.3v
d) 2.5v
Answer: c
Clarification: I2C uses only two bidirectional open drain lines, SDA and SCL. Typical voltages used are 5v or 3.3v, although system with other voltages is permitted.
6. What is the speed of I2C bus?
a) 100 kbits/s
b) 10 kbits/s
c) 75 kbits/s
d) 100 kbits/s and 10 kbits/s
Answer: d
Clarification: Common I2C bus speeds are the 100 kbits/s standard mode and the 10 kbits/s low speed mode, but arbitrarily low clock frequencies are also allowed.
7. Master transmits means _________
a) Master node is sending data to a slave
b) Master node is receiving data from slave
c) Slave node is transmitting data to master
d) Slave node is sending data to master
Answer: a
Clarification: There may be four potential modes of operation for a given bus device, although most devices only use a single role and its two modes:
-> Master transmit – Master node is sending data to a slave
-> Maser receive – Master node is receiving data from slave
-> Slave transmit – lave node is transmitting data to master
-> Slave receive – Slave node is sending data to master.
8. Who sends the start bit?
a) Master receive
b) Master transmit
c) Slave transmit
d) Slave receive
Answer: b
Clarification: The master is initially in master transmit mode by sending a start bit followed by 7 bit address of the slave.
9. Which is the I2C messaging example?
a) 24c32 EPROM
b) 24c32 EEPROM
c) 24c33 EEPROM
d) 24c33 EPROM
Answer: b
Clarification: The 24c32 EEPROM, which uses two request bytes that are called Address high and address low. These bytes are used to address bytes within the 32 kbit supported by that EEPROM.
10. Are pull up registers required in I2C?
a) True
b) False
Answer: a
Clarification: At physical layer, both SCL and SDA lines are of open drain design, thus pull up resistors are needed.
11. How many types of addressing structures are there in I2C?
a) 4 types
b) 3 types
c) 2 types
d) 5 types
Answer: c
Clarification: There are 2 addressing mode –> 7-bit addressing mode
–> 10-bit addressing mode.
12. All operating modes work under ____________
a) 11 kbit/s
b) 100 kbit/s
c) 15 kbit/s
d) 150 kbit/s
Answer: b
Clarification: There are several operating modes for I2C communication. All are compatible in that the 100 kbit/s standard mode is always used.
13. Which mode is highly compatible and simply tightens?
a) Fast mode
b) High speed mode
c) Ultra fast mode
d) Both fast and high speed mode
Answer: a
Clarification: Fast mode is highly compatible and simply tightens several of the timing parameters to achieve 400 kbit/s speed.
14. What is the speed for fast mode?
a) 100 kbit/s
b) 400 kbit/s
c) 150 kbit/s
d) 200 kbit/s
Answer: b
Clarification: Fast mode is highly compatible and simply tightens several of the timing parameters to achieve 400 kbit/s speed.
15. What is the speed for fast mode?
a) 100 kbit/s
b) 3.4 Mbit/s
c) 150 kbit/s
d) 200 kbit/s
Answer: b
Clarification: High speed mode is compatible with normal I2C devices on the same bus, but requires the master have an active pull-up on the clock line which is enabled during high speed transfers.