Raspberry Pi A User Manual page 269

The disadvantage of the Slice of Pi lies in its simplicity. Its compact size means that it is unsuitable
for the creation of larger or more complex prototypes, and while the header layout provides some
protection against short circuits, there's no protection against the use of 5 V components that can
damage the Pi's 3.3 V logic circuits. The labelling is also different to that used to typically describe
the Raspberry Pi's GPIO pins, which can lead to confusion when using a GPIO library not written
with the Slice of Pi in mind. Table 16-1 provides a mapping from one labelling system to another.
Table 16-1: Slice of Pi GPIO Mappings
Physical Pin Number
7
11
12
13
15
16
18
22
C H A P T E R 1 6
A D D - O N B O A R D S
Official Designation
GPIO Pin 4 (or General Purpose Clock 0)
GPIO Pin 17
GPIO Pin 18
GPIO Pin 27 (21 on Revision 1 boards)
GPIO Pin 22
GPIO Pin 23
GPIO Pin 24
GPIO Pin 25
Slice of Pi Label
GP7
GP0
GP1
GP2
GP3
GP4
GP5
GP6
253
Figure 16-3:
The Slice of Pi,
connected to the
Pi's GPIO port