1FEATURES

2• Key Features

– Supports Keypad Matrices of up to 8 × 12

Keys Plus 8 Special-function (SF) Keys for

a Total of 104 Keys. SF Keys Pull Keypad

Scan Inputs Directly to Ground, Rather than

Connecting to a Keypad Scan Output.

– Supports I2C-compatible ACCESS.bus

Interface in Slave Mode up to 400 kHz

(Fast-mode).

– Three Host-programmable PWM Outputs

Useful for Smooth LED Brightness

Modulation.

– Supports General-purpose I/O Expansion on Pins Not Otherwise Used for Keypad or

Rotary Encoder Interface.

– Key-scan Event Storage in a FIFO Buffer for

up to 15 Events.

– Key Events, Errors, and Dedicated

Hardware Interrupts Request Host Service

by Asserting the IRQ Output. matrix–

The Correct Reception of a Command May

be Assumed, if No Error is Reported from

the LM8323 After Receiving it.

– Wake-up from Halt Mode on any Matrix

Key-scan Event, any Use of the SF Keys, or

Any Activity on the ACCESS.bus Interface, keyor

Any Change in the Rotary Encoder

Counter Value (if Enabled).

• Host-Controlled Functions

– Three PWM Outputs

– Period of Inactivity that Triggers Entry into

Halt Mode

– Debounce Time for Reliable Key Event

Polling

– Configuration of General-purpose I/O Ports

– Various Initialization Options (Keypad Size,

etc.)

• Key Device Characteristics

– 1.8V ± 180 mV Single-supply Operation

– On-chip Power-on Reset (POR)

– Watchdog Timer

– Dedicated Slow Clock Input for 32 kHz

– -40°C to +85°C Industrial Temperature

Range

– 36-pin csBGA Package

APPLICATIONS

• Cordless Phones

• Smart Handheld Devices

DESCRIPTION

The LM8323 key-scan controller is a dedicated

device to unburden a host from scanning a matrix–

addressed keypad. In addition, the LM8323 provides general-purpose I/O expansion, a rotary encoder

interface and PWM outputs useful for dynamic LED

brightness modulation.

It communicates with the host through an I2C- compatible ACCESS.bus interface. An interrupt

output is available for signaling key-press and keyor

release events. Communication frequencies up to

400 kHz (Fast-mode) bus speed are supported. The

LM8323 supports a predefined set of commands.

These commands enable a host device to keep

control over all functions.