Understanding the Buttons and LEDS, and how to connect them to the MCP23017 board
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matt shepherd

Created Jun 06, 2023

Understanding the Buttons and LEDS, and how to connect them to the MCP23017 board

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1

The 8x Button Matrix

This is an 8-button matrix configuration, where multiple buttons share a common cable or row, while their differentiation is achieved through columns. For instance, buttons 1 and 2, which correspond to play and pause functions, are assigned to Row 1. Pressing button 1 activates Column 1, while the pause function is associated with Column 2.

And hopefully, with a bit of luck, the corresponding LED should light up when a button is pressed.

In a nutshell: even though there are 8 buttons you only have 6 wires.

The 8x Button Matrix
2

Remove the Button and LED circuit from the main board

Once you have delicately detached the button and LED ribbon cables from the old circuit board, the next step involves separating and extending the individual wires using your proficient soldering skills (don't forget to use the heat shrinks).

Both ribbon cables are connected to the MCP23107 board: LEDs are on row A (PA0-PA7) and the Rows and Columns are on row B (PB0-PB5)

Remove the Button and LED circuit from the main board
3

MCP23017 wire-up pin-out

MCP23017 wire-up pin-out
4

Finished board

Finished board
Well done!
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