The LM8327 GenI/O-Expander and Keypad Controller is a dedicated device to unburden a host processor from scanning a matrix-addressed keypad and to provide flexible and general purpose, host-programmable input/output functions. Three independent PWM timer outputs are provided for dynamic LED brightness modulation.

It communicates with a host processor through an I2C-compatible ACCESS.bus serial interface. It can communicate in Standard (100 kHz) and Fast-Mode (400 kHz) in slave Mode only.

All available input/output pins can alternately be used as a direct key input connection, an input or an output in a keypad matrix, or as a host-programmable general purpose input or output.

Any pin programmed as an input can also sense hardware interrupts. The interrupt polarity (“high-to-low” or “low-to-high” transition) is thereby programmable.

The LM8327 follows a predefined register based set of commands. Upon startup (power on) a configuration file must be sent from the host to setup the hardware of the device.

• Internal RC Oscillator, no External Clock Required
• Internal PWM Clock Generation, no External Clock Required
• Programmable I2C-compatible ACCESS.Bus Address (Default 0x8A)
• Support for Keypad Matrices of up to of 8 x 12 Keys, Plus 8 Special Function (SF) Keys, for a Full 104 Key Support
• Support for up to 26 Direct Connect Keys
• I2C-Compatible ACCESS.Bus Slave Interface at 100 kHz (Standard-Mode) and 400 kHz (Fast-Mode)
• Three Host-Programmable PWM Outputs for Smooth LED Brightness Modulation
• Supports General-Purpose I/O Expansion on Pins not Otherwise Used for Keypad or PWM Output
• 15-byte Key Event Buffer
• Multiple Key Event Storage
• Key Events, Errors, and Dedicated Hardware Interrupts Request Host Service by Asserting an IRQ Output
• Automatic HALT Mode for Low Power Operation
• Wake-Up from HALT Mode on any Interface (Rising Edge, Falling Edge or Pulse)
• Three PWM Outputs with Dedicated Script Buffer for up to 32 Commands
• Register-Based Command Interpreter with Auto-Increment Address

Features, Host-Controlled

• PWM Scripting for 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.)

Features, Key Device

• 1.8V ± 10% Single-Supply Operation
• On-Chip Power-On Reset (POR)
• ESD Glitch Filter on RESETN Pin
• Watchdog Timer
• Dedicated Slow Clock Input for 32 kHz up to 8MHz
• −40°C to +85°C Temperature Range
• 36-pin csBGA Package