NXP Semiconductors’ LPC82x Touch Solution is a royalty-free capacitive touch-sensing solution in software which is designed to run on NXP’s LPC82x family of microcontrollers. It uses the MCU’s GPIO functionality and an analogue comparator input to implement a touch-sensing circuit.
The microcontroller’s GPIOs are used to emulate a switched-capacitor integrator circuit which senses the relative change in the capacitance of a touch-sensing element when touched by a finger. The external circuitry consists of just one capacitor, and a sensor layout interfaced to the microcontroller.
A touch-sensing library provided by NXP can be used to implement any user interface which requires touch-sensing buttons, a slider or wheel, or more complex two-dimensional touch inputs. Designers may evaluate the touch-sensing software and the LPC824 MCU on the OM13071 development kit.
- LPCXpresso824-MAX development board
- LPC824 capacitive touch-sensor shield with LCD display
- GUI for visualising and analysing the touch data