ADP5588 Datasheet | Analog Devices

FEATURES 18-GPIO port expander or 10 × 8 keypad matrix GPIOs configurable to GPIs, GPOs, and keypad rows or columns Dual light sensor inputs (C8 and C9) I2C interface I2C register read autoincrement 1.8 V to 3.0 V operation Keypad lock capability Open-drain interrupt output Key press and key release interrupts GPI interrupt with level programmability Programmable pull-ups Key event counter with overflow interrupt 50 μs debounce on the reset line and GPIs 1 μA typical idle current, 55 μA typical polling current drain for one key press Small 4 mm × 4 mm LFCSP package APPLICATIONS Keypad and I/O expander designed for QWERTY type phones that require a large keypad matrix GENERAL DESCRIPTION The ADP5588 is an I/O port expander and keypad matrix designed for QWERTY type phones that require a large keypad matrix and expanded I/O lines. I/O expander ICs are used in mobile platforms as a solution to the limited number of GPIOs available in the main processor. In its small 4 mm × 4 mm package, the ADP5588 contains enough power to handle all key scanning and decoding and flag the processor of key presses and releases via the I2C® interface and interrupt. It frees the main microprocessor from having to monitor the keypad, thereby minimizing current drain and increasing processor bandwidth. It is also equipped with a buffer/FIFO and key event counter to handle and keep track of up to 10 unprocessed key or GPI events with overflow wrap and interrupt capability. The ADP5588 has a keylock capability with an option to trigger or not trigger an interrupt at key presses and releases. All munication to the main processor is done using one interrupt line and two I2C-patible interface lines. The ADP5588 can be configured to have a keypad matrix of up to 8 rows × 10 columns (a maximum of 80 keys). Mobile I/O Expander and QWERTY Keypad Controller FUNCTIONAL BLOCK DIAGRAM REF VOLTAGE GND 19 VCC 21 C9 C9 SCL 23 SDA 22 CONTROL REGISTERS CONTROL INTERFACE REF...