What is a shield?

A shield is a printed circuit board (PCB) that attaches to a microcontroller and gives it additional capabilities that it doesn’t natively ship with. Most shields are the same size as the microcontroller they are meant to work with. An example shield for the Arduino Portenta H7 microcontroller is shown in the following figure:

Figure 3.1 – Arduino Portenta Vision Shield – Ethernet

Shields are meant to be mounted on top of the microcontroller. They receive power from the microcontroller, so they don’t have a power connector. Most shields have stacking headers, so you can mount other shields on top of them.

There is another group of PCBs called carriers.

What are carriers?

Carriers are boards, but they do not mount onto a microcontroller. Instead, the microcontroller mounts onto the carrier. Carriers provide connectors for plugging other devices into the microcontroller. Arduino currently provides the...