Description:

This is a breakthrough board for Freescale's mpr121qr2. The MPR121 capacitive touch sensor controller is driven via an I2C interface. The chip can control up to twelve electrodes, as well as a simulated thirteenth electrode. The mpr121 also has eight LED drive pins. When these pins are not configured as electrodes, they can be used to drive light emitting diodes.

There are one or four athletes at the bottom of the board, all of which are set (closed) by default. An address jumper is added to the ground pin. In the sense, the chip's default I2C address will be 0x5a. If you need to change the chip's address (by adding it to a different pin by shorting), make sure you open the jumper first. The jumper connects SCL and SDA and interrupts the pull-up resistor of pin 10K. If you don't need a pull-up resistor, you can open the jumper by cutting traces.

There are no regulations on the board, so the voltage provided should be between 2.5 and 3.6 vdc. The VREG pin is grounded through a 0.1uF capacitor, which means the connection, unless you modify the board, you cannot operate mpr121 (1.71-2.75vdc) in low supply voltage mode.