I2C vs SPI decision matrix in Embedded C - Quick Revision & Key Differences

Recall & Review

beginner

What does I2C stand for and what is its main use?

I2C stands for Inter-Integrated Circuit. It is mainly used for communication between multiple chips on the same board using just two wires: one for data and one for clock.

beginner

What does SPI stand for and what is its main use?

SPI stands for Serial Peripheral Interface. It is used for fast communication between a master device and one or more slave devices using separate lines for data and clock.

beginner

Which protocol uses fewer wires: I2C or SPI?

I2C uses fewer wires (2 wires) compared to SPI (at least 4 wires). This makes I2C simpler for wiring but sometimes slower.

intermediate

Which protocol is generally faster: I2C or SPI?

SPI is generally faster than I2C because it uses separate lines for sending and receiving data and can run at higher clock speeds.

intermediate

When should you choose I2C over SPI?

Choose I2C when you need to connect multiple devices with minimal wiring and moderate speed is acceptable. It is good for simple sensor networks and low pin count.

How many wires does I2C use for communication?

A 2 wires

B 3 wires

C 4 wires

D 1 wire

I2C uses two wires: one for data (SDA) and one for clock (SCL).

Which protocol typically supports multiple masters on the same bus?

A UART

B SPI

C I2C

D CAN

I2C supports multiple masters on the same bus, allowing more flexible communication.

Which protocol usually requires more pins on the microcontroller?

A I2C

B SPI

C Both require the same

D Neither requires pins

SPI requires at least 4 pins (MISO, MOSI, SCLK, SS) plus one SS pin per slave, so it uses more pins.

Which protocol is better for high-speed data transfer?

A I2C

B Neither supports high speed

C Both are equally fast

D SPI

SPI is better for high-speed data transfer due to its dedicated data lines and higher clock rates.

If you want to connect many devices with minimal wiring, which protocol is preferred?

A I2C

B USB

C UART

D SPI

I2C uses only two wires and supports multiple devices, making it ideal for minimal wiring.

Explain the main differences between I2C and SPI protocols.

Think about wiring, speed, and how many devices can connect.

Describe a scenario where you would choose SPI over I2C and why.

Consider when fast communication is more important than wiring simplicity.