Mobile I/O Expander and QWERTY Keypad Controller Data Sheet ADP5588 FEATURES FUNCTIONAL BLOCK DIAGRAM 18-GPIO port expander or 10 8 keypad matrix REF ADP5588 VO L T AG E GPIOs configurable to GPIs, GPOs, and keypad rows or columns GND 19 C9 V Dual light sensor inputs (C8 and C9) CC C9 C9 21 18 2 I C interface SCL 23 2 REF I C register read autoincrement CO NT RO L CO NT RO L SDA VO L T AG E 22 REG I ST ERS INT ERF ACE C8 1.8 V to 3.0 V operation C8 C8 17 RST 20 Keypad lock capability INT 24 Open-drain interrupt output Key press and key release interrupts GPI interrupt with level programmability 12 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Programmable pull-ups Key event counter with overflow interrupt 50 s debounce on the reset line and GPIs Figure 1. 1 A typical idle current, 55 A 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 When used for smaller keypad matrices, unused row and GENERAL DESCRIPTION column pins can be reconfigured to act as general-purpose The ADP5588 is an I/O port expander and keypad matrix inputs, outputs, or light sensor inputs. R0, R1, R2, R3, R4, R5, R6, designed for QWERTY type phones that require a large keypad and R7 denote the row pins of the matrix, while C0, C1, C2, C3, matrix and expanded I/O lines. I/O expander ICs are used in C4, C5, C6, C7, C8, and C9 denote the column pins. At power-up, mobile platforms as a solution to the limited number of GPIOs all rows and columns default as GPIs and must be programmed to available in the main processor. function as part of the keypad matrix, GPOs, or light sensor inputs. In its small 4 mm 4 mm package, the ADP5588 contains In addition to keypad and GPIO functionalities, C8 and C9 can enough power to handle all key scanning and decoding and flag also be configured as light sensor inputs. 2 the processor of key presses and releases via the I C interface When configured as keypad lines, the function of the C8 and and interrupt. It frees the main microprocessor from having to C9 lines is straightforward: the control interface disconnects monitor the keypad, thereby minimizing current drain and these lines from the comparator inputs, disables the light sensor increasing processor bandwidth. It is also equipped with a comparator, and connects them to the keypad columns of the buffer/FIFO and key event counter to handle and keep track of keypad matrix. When used as light sensor comparator inputs, up to 10 unprocessed key or GPI events with overflow wrap and the control interface disconnects these pins from the keypad, interrupt capability. enables the comparators, and connects these lines to the com- The ADP5588 has a keylock capability with an option to trigger parator inputs. Two external capacitors (0.1 F) are required or not trigger an interrupt at key presses and releases. All com- when these pins are configured as light sensor inputs. When munication to the main processor is done using one interrupt line used as GPIOs, these pins are removed from the keypad and the 2 and two I C-compatible interface lines. The ADP5588 can be light sensor interface, and the light sensor comparators are configured to have a keypad matrix of up to 8 rows 10 columns disabled, along with the logic for the sensors. (a maximum of 80 keys). Rev. D Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20082019 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. 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R7 R6 R5 R4 R3 R2 R1 R0 C0 C1 C2 C3 C4 C5 C6 C7 07673-001ADP5588 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Keypad Operation .........................................................................7 Applications ....................................................................................... 1 General-Purpose Inputs and Outputs ........................................9 2 Functional Block Diagram .............................................................. 1 I C Programming and Digital Control ........................................ 14 General Description ......................................................................... 1 Registers ....................................................................................... 15 Revision History ............................................................................... 2 Register Descriptions ................................................................. 16 Specif icat ions ..................................................................................... 3 Comparator Register Descriptions .......................................... 21 DC Electrical Characteristics ...................................................... 3 Applications Information .............................................................. 24 Absolute Maximum Ratings ............................................................ 5 Applications Overview .............................................................. 24 Thermal Resistance ...................................................................... 5 Keypad Current .......................................................................... 24 ESD Caution .................................................................................. 5 Backlight Control Application .................................................. 24 Pin Configuration and Function Descriptions ............................. 6 Outline Dimensions ....................................................................... 26 Theory of Operation ........................................................................ 7 Ordering Guide .......................................................................... 26 REVISION HISTORY 10/2019Rev. C to Rev. D 4/2009Rev. A to Rev. B Changes to Table 18 ........................................................................ 16 Changes to Title ................................................................................. 1 Updated Outline Dimensions ....................................................... 26 Changes to Ordering Guide .......................................................... 26 Changes to Ordering Guide .......................................................... 26 11/2008Rev. Sp0 to Rev. A 2/2012Rev. B to Rev. C Changes to Table 12 .......................................................................... 8 Changes to Table 27 ........................................................................ 18 Rev. D Page 2 of 28