Version 18
    Atmel > Sensing > Capacitive Touch >
    • Visualize discrete touch buttons and LEDs per channel touch indication
    • Battery powered
    • Stand-alone
    • On-board connections for debugging

    The EVK1040A kit Evaluates all functions of the Atmel AT42QT1040 touch sensor controller. The kit provides a convenient reference design and lets designers visualize discrete touch buttons and LEDs for per-channel touch indication. Movable jumpers on the board allow desingers to test Adjacent Key Suppression® (AKS) functionality and speed settings. The EVK1040A is battery powered and works as a standalone system. On-board connections can be used to access debug data from the chip. The AT42QT1040 (QT1040) IC is a convenient and easy-to-use touch sensor controller for up to four capacitive touch keys.

    The EVK1040A can be connected to external electrodes by soldering to pads at J5. Disconnect K0, K1, K2 and K3 by cutting through the connecting tracks to J5. The four discrete outputs from the QT1040 can be accessed at J3. If connected externally, remove RL0, RL1, RL2 and RL3. The QT1040 has a debug mode that can be entered by applying a short circuit across CS3 at power-up and removing the short circuit within 5 seconds. Using this, the internal parameters of the QT1040 can be monitored externally through connections available at J3.

    C0, C1, C2 and C3 can be replaced with different value X7R capacitors to change the sensitivity of each of the channels K0, K1, K2 and K3 respectively. Increasing the capacitor values will increase sensitivity and decreasing the capacitor value will decrease the sensitivity. (All flux residues should be removed after component replacement.) The AKS mode is changed by moving the 2-way link fitted to J1 as indicated. For the change to become active, cycle power by sliding the Power switch to OFF then ON.

    The QT1040 response speed can be changed on the EVK1040A for either a fast response (16ms), or a slightly slower response (64ms) (with the benefit of reduced power consumption) by moving the 2-way link fitted to J2 as indicated. For the change to become active, cycle power by sliding the Power switch to OFF then ON.

    Applications: Mobile, consumer, white goods, toys, kiosks, POS.

    • EVK1040A Board
    • CR2032 Battery, 3V, 235mAh
    • Two Sample AT42QT1040-MMH ICs
    • EVK1040A User Guide