Texas Instruments - QWERTY-capable I2C keypad controller

27th October 2009

ES Admin

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Texas Instruments has introduced the TCA8418, a keypad scan device that can generate an interrupt output signal using a three-key combination such as CTRL-ALT-DEL, which frees up the processor from scanning the keypad for presses and releases, saving power and bandwidth.

The TCA8418 supports applications such as smartphones, netbooks and mobile Internet devices (MID).

Key features and benefits of the TCA8418

· The key controller includes an oscillator that debounces at 50 us and maintains a 10-byte FIFO of key-press and key-release events, which can store up to 10 keys with overflow wrap capability.

· An interrupt (/INT) output can be configured to alert key presses and releases, either as they occur or at maximum rate.

· Power supply voltage operating range of 1.65 V to 3.6 V allows for glueless interface to today’s most advanced processors.

· Eighteen general purpose inputs/outputs (GPIO) can be configured into eight inputs and ten outputs, which supports an 8 x 10 keypad array (80 buttons) through the I2CTM interface.

· Low standby (idle) current consumption of 3 uA extends battery life in portable devices.

· Can be used with a processor that has limited GPIOs, and is compatible with a variety of advanced processors including many of TI’s OMAP™ 3 applications processors.