Chapter 14
The GPIO Port
THE RASPBERRY PI’S general-purpose input-output (GPIO) port is located on the top left of the printed circuit board. The port is fitted with two rows of 20 2.54 mm male header pins, except in the case of the Raspberry Pi Zero where header pins must be soldered; this is explained at the end of this chapter. The spacing of these headers is particularly important: 2.54 mm pin spacing (0.1 inches in imperial measurements) is a very common sight in electronics and is the standard spacing for prototyping platforms that include stripboards and breadboards.
Identifying Your Board Revision
All modern Raspberry Pis, bar the industrial-friendly Raspberry Pi Compute Module design, feature a standardised 40-pin GPIO header. If you have a Raspberry Pi Model A+, Model B+, Raspberry Pi 2, Raspberry Pi 3, or Raspberry Pi Zero, you have the most recent version of the GPIO port design and should use the full-size GPIO pinout diagram shown as Figure 14-1 under “GPIO Pinout Diagrams”.
FIGURE 14-1: The Raspberry Pi’s GPIO port and its pin definitions
There are two other types of GPIO port design, exclusive to older Raspberry Pi hardware. These are immediately distinguishable from the newer 40-pin design, as they have only 26 pins laid out in two rows of 13. This shorter GPIO header can be found on the Raspberry Pi Model A and Model B. If you own an original Raspberry Pi ...
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