GPIO/keypad controllers simplify interconnect circuits
1 min read
Analog Devices has launched the ADP5585 and ADP5589 general purpose input/output port expander and keypad matrix controller for devices that require expanded I/O lines or mechanical keypads up to QWERTY size.
The new modules are said to feature the industry's lowest active current drain and integrated programmable logic/pwm. They are optimised to save battery life in portable devices by consuming less than 30µA when keys are pressed and less than 1uA when the keys are idle.
Both keypad controllers support multiple, simultaneous key press detection and communicate presses and releases in a chronological order via a 16byte FIFO. In addition to the built in programmable logic devices, two programmable reset generators allow designers to programme keys, GPIOs, and/or logic changes to generate a reset signal to restart a locked up processor.
Both devices are available in LFCSP and WLCSP packages. According to ADI, they free up the main processor from having to monitor the keypad, handle all key scanning and decoding functions and use an interrupt line to flag the main processor when new key events have occurred. The modules are suitable for devices with front panel keypads that need to expand the number of GPIO ports without increasing pin count.
Both the ADP5585 and ADP5589 are equipped with FIFO registers that store up to 16 events, which are then read back by the processor through an I2C compatible interface. Evaluation boards and Linux software drivers are available to implement new designs.
