GENERAL DESCRIPTION

OVERVIEW

The System Energy Manager is a highly integrated microcontroller that provides several key features for systems including key scanning and control, battery and power management, as well as two 2–Wire serial I/O Ports. It incorporates the Dallas 8051–compatible high–speed microcontroller core which has been redesigned to eliminate wasted clock and memory cycles. Every standard 8051 instruction is executed between 1.5 and 3 times faster than the original for the same crystal speed.

DETAILED FEATURE SUMMARY

• High Speed 80C32 Compatible Core:

– High performance 4 clocks / machine cycle (8032 = 12)

– Low Power: typically 1/3 power for equivalent 8032 throughput

– Maximum clock speed up to 25 MHz at 5.0V

– Ultra–low stop mode power (typ. 1 uA) and “IDLE” mode (typ. 10 mA)

– Multiple wake–up sources from STOP including key scan, 2–wire, host I/F, or external interrupt

– Three 16–bit timers, 1 serial port

– 256 byte scratchpad

– 256 bytes MOVX RAM

• Keyboard Control:

– Replaces 8042 and key scan microcontroller

– 2 Parallel I/O ports for key scan outputs

– One interrupt–driven 8–bit input port to initiate key–scan sequence

• Input/Output:

– Total of eleven 8–bit I/O ports; all pins can be individually programmed to serve as general purpose digital input/output.

– Each 8–bit port supports one or more special functions:

Port 0, 2, 3: External program / data memory interface

Port 1, 3: UART, 2–Wire serial, timers, and external interrupt I/O.

Port 4, 8, 9: Key scan input / output

Port 5: A/D inputs

Port 6: PWM Outputs

Port 7: Activity monitor, LED Control

Port 10: GPIO

• Analog Input/Output:

– Eight–channel, 10–bit A/D with power down mode supports charging NiMH rechargeable cells

– 4–channel, 8–bit PWM supports LCD brightness and contrast control

• 2–Wire Bi–directional Serial Buses

– Master/slave multi–drop operation

– Manages on–board slaves or external I/O devices

• Power Control

– Generates system power on reset

– Programmable power down pin states