Interfacing a 4×4 Matrix keypad with an 8-Bit GPIO expander
An application note from Microchip: Interfacing a 4×4 Matrix keypad with an 8-Bit GPIO expander This application note discusses interfacing a 4×4 matrix keypad with MCP23X08 8-Bit GPIO Expander. This application note references the MCP23X08/17 GPIO Expander Keypad/LCD Demo Board (GPIODM-KPLCD). GPIO Expanders provide easy I/O expansion using standard serial interfaces such as I2C and SPI. …
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