GPIO pin numbering (BCM vs BOARD) in Raspberry Pi - Quick Revision & Key Differences

Recall & Review

beginner

What does BCM stand for in Raspberry Pi GPIO pin numbering?

BCM stands for Broadcom SOC channel. It refers to the pin numbering based on the Broadcom chip's internal numbering.

beginner

What does BOARD mean in Raspberry Pi GPIO pin numbering?

BOARD refers to the physical pin numbering on the Raspberry Pi's GPIO header, counting pins from 1 to 40 based on their physical location.

intermediate

Why might you choose BCM numbering over BOARD numbering?

BCM numbering is useful because it matches the chip's internal pin names, making code more consistent across different Raspberry Pi models.

beginner

How do you set the pin numbering mode to BCM in Python using RPi.GPIO?

You use the command: GPIO.setmode(GPIO.BCM) to select BCM numbering mode.

intermediate

What could happen if you confuse BCM and BOARD numbering when wiring your Raspberry Pi?

You might connect to the wrong pins, causing your circuit to not work or even damage your Raspberry Pi or connected components.

Which GPIO pin numbering mode uses the physical pin locations on the Raspberry Pi header?

A BOARD

B BCM

C WIRINGPI

D GPIO

BOARD numbering counts pins by their physical position on the header.

What command sets the GPIO numbering mode to BCM in Python's RPi.GPIO library?

A GPIO.mode(GPIO.BCM)

B GPIO.setmode(GPIO.BOARD)

C GPIO.setup(GPIO.BCM)

D GPIO.setmode(GPIO.BCM)

GPIO.setmode(GPIO.BCM) sets the numbering to Broadcom SOC channel mode.

If you want your code to work on different Raspberry Pi models without changing pin numbers, which mode is better?

A Neither

B BOARD

C BCM

D Both are the same

BCM numbering refers to the chip pins, which stay consistent across models.

How many pins does the Raspberry Pi 40-pin header have in BOARD numbering?

A 40

B 20

C 28

D 26

The Raspberry Pi 40-pin header has 40 physical pins numbered 1 to 40.

What is a risk of mixing up BCM and BOARD numbering when connecting hardware?

A Code runs faster

B Pins may be connected incorrectly causing failure or damage

C No risk, they are interchangeable

D GPIO pins become disabled

Wrong pin connections can cause circuits to fail or damage components.

Explain the difference between BCM and BOARD GPIO pin numbering on a Raspberry Pi.

Think about chip vs physical layout.

Describe why choosing the correct GPIO pin numbering mode is important when programming Raspberry Pi hardware.

Consider what happens if you wire wrong pins.