I2C bus architecture (SDA, SCL) in Embedded C - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does SDA stand for in I2C bus architecture?

SDA stands for Serial Data Line. It is the line used for transferring data between devices on the I2C bus.

beginner

What is the role of the SCL line in I2C communication?

SCL stands for Serial Clock Line. It provides the clock signal that synchronizes data transfer on the I2C bus.

intermediate

Why are SDA and SCL lines open-drain/open-collector in I2C?

They are open-drain/open-collector to allow multiple devices to share the bus without conflicts. Devices can only pull the line low, and a pull-up resistor brings the line high when no device is pulling it low.

intermediate

How does the master device use SDA and SCL to start communication on the I2C bus?

The master generates a START condition by pulling SDA low while SCL is high. This signals all devices that a communication session is beginning.

intermediate

What happens on the I2C bus when the master sends a STOP condition?

The master releases SDA from low to high while SCL is high. This signals the end of communication and frees the bus for other devices.

What does the SDA line do in I2C communication?

A Transfers data between devices

B Provides the clock signal

C Supplies power to devices

D Resets the bus

SDA is the Serial Data Line used to transfer data between devices on the I2C bus.

Why are pull-up resistors used on SDA and SCL lines?

A To allow devices to pull lines low safely

B To provide power to the devices

C To speed up data transfer

D To prevent devices from communicating

Pull-up resistors ensure the lines go high when no device pulls them low, enabling safe open-drain communication.

What condition does the master generate to start communication on the I2C bus?

A STOP condition

B START condition

C RESET condition

D ACK condition

The START condition is generated by pulling SDA low while SCL is high to begin communication.

Which line carries the clock signal in I2C?

A SDA

B SCL

C VCC

D GND

SCL is the Serial Clock Line that provides the clock signal for synchronization.

What does an open-drain configuration allow on the I2C bus?

A Multiple devices to drive the line high simultaneously

B Multiple devices to safely pull the line low without conflict

C Only one device to communicate at a time

D Faster data transfer speeds

Open-drain allows multiple devices to pull the line low safely, avoiding conflicts on the bus.

Explain the roles of SDA and SCL lines in the I2C bus architecture.

Think about how devices talk and keep time on the bus.

Describe how the I2C master starts and stops communication using SDA and SCL lines.

Focus on the changes in SDA line while SCL is high.