Circuit Analysis

Take a moment to look over the components. The circuit diagram is ment to be used a reference for visualizing wired connections.

The length of wires, dimension of components, and positions are not exact. 

Wired Connections

The four main components (Raspberry Pi A+, TFP401 display driver, 2.8W Amplifier and PowerBoost500C) will be powered by the PowerBoost 500C and a 6600mAh Lithium Ion battery via JST cable. To power the circuit on/off, a slide switch is connected to the EN,and GND pins on the PowerBoost500C. 

The 2.8W Amplifier is connected to GND and +Postive pins on the PowerBoost 500C. A right-angle 3.5mm stereo plug to pigtail cable is wired to the amp and connected to the audio jack on the Pi A+. Two mini metal speakers are wired to the audio output pins on the amp.

The 5V and GND pins on TFP401 display driver are wired to the 5V and GND pins on the PowerBoost500C. A flat HDMI cable is connnected from the TFP401 to the Raspberry Pi A+.

The 5" HDMI display uses a 40-pin FPC extension board to connect the TFP401 display driver to the screen.

Raspberry Pi GPIO

Below is a legend of each connection. It includes the pin number, name and connection. The GPIO graphic matches the order of the pins. Use this to reference which buttons connect to the GPIO.

How Do I Read This?

The pin# is the actual number of the pin in series. The numbers go from left to right, top to bottom. The name is the title for a given pin entity. Note the GPIO # does not match the pin number. The connection is the button or wire that needs to be assoicated with the pin.

The GPIO # will be associated with the Input value in the retrogame.c file.

In most cases, you should print out the legend (on physical paper) and use it as a cheatsheet while assembling the circuit.

Button Connections

UP        - GPIO 17, Pin 11
DOWN - GPIO 27, Pin 13
LEFT    - GPIO 22, Pin 15
RIGHT  - GPIO 23, Pin 16
Select  - GPIO 18, Pin 12
Start    - GPIO 4, Pin 07
A         - GPIO 24, Pin 18
B         - GPIO 10, Pin 19
X         - GPIO 09, Pin 21
Y         - GPIO 25, Pin 22
L         - GPIO 11, Pin 23
R         - GPIO 08, Pin 24

Color Codes

Black    - Ground
Red       - DC Power 
Blue      - SDA1, I2C
Green   - GPIO
Orange - TX/RX
Pink       - SPI
Yellow  - I2C ID EEPROM

This guide was first published on Jan 14, 2015. It was last updated on Mar 08, 2024.

This page (Circuit Diagram) was last updated on Dec 22, 2014.

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