July 18, 2014 AT 2:00 pm

Controlling the Raspberry Pi’s GPIOs using direct register access in C++

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Via Hertaville.

In this blog entry I will present the mmapGpio class that provides basic access to all the GPIO’s on the RPI’s 26-pin header using direct register access. The advantage of this approach to GPIO control is that one can bypass Linux and talk directly with the GPIO registers which enables much faster GPIO toggling speeds. Using this approach I was able to get GPIO toggling speeds that exceed 25MHz!!!! That’s much faster than the toggling speeds that can be achieved using the safer but slower SYSFS approach to GPIO control.

The mmapGpio class is intentionally designed to be simple but useful. A great feature of this class is that a single instance can be used to control the all the RPI’s GPIOs. The mmapGpio class with two examples and makefiles can be downloaded from here.

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