DS80CH11

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 2Wire serial I/O Ports.  It incorporates the Dallas 8051compatible highspeed microcontroller core which has been rede-signed 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.  Looking at it another way, the highspeed core achieves the same throughput as a stan-dard 8051 while using much less power as a result of fewer required clock cycles.  As a result, the firmware can easily support many tasks required by mobile sys- tems within a single component.

The controller is designed to offload battery and power management tasks from the host CPU and thereby make possible an efficient solution for systems.   In addi-tion to the microcontroller core, it incorporates an 8channel, 10bit A/D converter with external refer-ence so that its firmware can perform battery manage-ment tasks without burdening the host CPU.  A fourchannel 8bit pulsewidth modulator allows digital control of functions such as LCD contrast and bright-ness.  An 8bit port is provided for key scan inputs.  A total of 88 parallel I/O pins are available for key scan-ning, system configuration, and power management control.

The System Energy Manager scans a key matrix and interfaces to the host CPU via an 8042compatible port.The benefits of sophisticated power management and permanently powered functions are thereby attained without adding to the system's chip count.

Two 2wire, bidirectional serial buses are incorpo- rated to facilitate the management of slave peripheral devices on the motherboard, such as digital tempera-ture sensors and potentiometers, and to support exter-nal lowspeed I/O devices such as monitor configura-tion channels, pen tablets, and joysticks.

Because a direct interface to the Xbus is provided, the controller is not dependent on a particular core logic chip or chip set.  Independent chip select inputs for the keyboard controller, power management #1, and power management #2 registers are provided.