Raspberry Pi A, User Manual, Page: 277 / 314

C H A P T E R 1 6
A D D - O N B O A R D S
261
Figure 16-10:
Connecting a
potentiometer
to the
Gertboard’s
ADC pins
Finally, the Gertboard provides access to a 28-pin microcontroller, which can be fitted to a
socket located on the board itself. When fitted, the Gertboard can be wired to address either
the Raspberry Pi’s GPIO port or the microcontroller, or a combination of the two. The
Gertboard is designed to operate with an Atmel ATmega168 or ATmega328 microcon-
troller—the same type of microcontroller used in the Arduino prototyping project. When
fitted, you can write programs for the Gertboards’ ATmega microcontroller in the Atmel IDE,
giving the Pi a useful level of compatibility with the wide array of existing ATmega-targeted
software available to download. It also gives the Pi the ability to address external hardware in
a real-time manner, with the microcontroller taking over responsibility for hardware inter-
facing and simply providing feedback to the Pi.