Appendix B. Raspberry Pi Pinouts
Raspberry Pi 400/4/3/2 Model B, B+, A+, Zero
Figure B-1 shows the pinout for the current 40-pin general-purpose input/output (GPIO) Raspberry Pi.
Figure B-1. 40-pin Raspberry Pi GPIO pinout
Raspberry Pi Model B revision 2, A
If you bought one of the early 26-pin Raspberry Pis, then it is most likely to be a model B revision 2 board, as shown in Figure B-2. (If you have one of these first editions of the Raspberry Pi, hang on to it; it might be valuable one day.)
Figure B-2. Raspberry Pi model B revision 2 and model A GPIO pinout
Raspberry Pi Model B revision 1
The very first released version of the Raspberry Pi model B (revision 1) has some minor pinout differences to the revision 2 that followed. This is the only version of the Raspberry Pi that is not compatible with later pinouts. The incompatible pins that changed are highlighted in bold in Figure B-3.
Figure B-3. Raspberry Pi model B revision 1 GPIO pinout
Raspberry Pi Pico
Although the Raspberry Pi Pico also has a 40-pin connector, the connections are entirely different, as shown in Figure B-4.