1FEATURES

2• 8 × 8 Standard Keys

• 8 Special Function Keys (SF Keys) Providing a

Total of 72 Keys for the Maximum Keyboard

Matrix

• ACCESS.Bus (I2C-compatible) Communication

Interface to the Host

• Four General Purpose Host Programmable I/O

Pins with Two Optional (Slow) External

Interrupts

• 15-byte FIFO Buffer to Store Key Pressed and

Key Released Events

• Error Control with Error Reports on (FIFO

Overrun, Keypad Overrun, Invalid Command)

• Host Programmable PWM

• Host Programmable Active Time and

Debounce Time

APPLICATIONS

• Mobile Phones

• Personal Digital Assistants (PDAs)

• Smart Handheld Devices

• Personal Media Players

DESCRIPTION

The LM8333 Mobile I/O Companion offloads the

burden of keyboard scanning from the host, while

providing extremely low power consumption in both

operational and standby modes. It supports keypad

matrices up to 8 × 8 in size (plus another 8 special-

function keys), for portable applications such as

cellphones, PDAs, games, and other handheld

applications.

Key press and release events are encoded into a

byte format and loaded into a FIFO buffer for retrieval

by the host processor. An interrupt output (IRQ) is

used to signal events such as keypad activity, a state change on either of two interrupt-capable general-

purpose I/O pins, or an error condition. Interrupt and

error codes are available to the host by reading

dedicated registers.

Four general-purpose I/O pins are available, two of

which have interrupt capability. A pulse-width

modulated output based on a host-programmable

internal timer is also available, which can be used as

a general-purpose output if the PWM function is not

required.

To minimize power, the LM8333 automatically enters

a low-power standby mode when there is no keypad,

I/O, or host activity.

The device is packaged in a 32–pin WQFN and a

49-pin csBGA. Both are chip-scale packages.