ACPI-Compliant Smart Battery and Keyboard Controller
If you're designing a portable computing platform that works with either a single or a multiple battery supply, take a look at this news from Usar Systems (New York, NY). The company is continuing its trend of assisting OEM designers by means of preprogrammed and ACPI (Advanced Configuration and Power Interface) compliant silicon.
As an open industry specification--originally derived by Intel, Microsoft, and Toshiba America--ACPI enables an operating system (OS) to implement system-directed power management. ACPI is a standardized way to integrate power management throughout a system's hardware, OS, and applications software. The spec defines a register-level interface to core power-management functions and a descriptive interface for additional hardware. In short, it lets you design a spectrum of power-management features with different hardware designs while using the same OS driver.
Safety First
Usar's latest less-than-$7 chip is a safety-oriented, readily modified, 8042-type dedicated controller offering command of keyboard and mouse functions. But, the ACPITroller II UR8HC359 chip also serves as an SMBus smart battery host, touting three zero-power SMBus ports. That will save board real-estate in cramped quarters. Nice.
The three ports can each be dedicated to communicating with a smart battery or smart battery peripheral. No continuous polling of batteries is needed--saving power in a portable computing system.
SMBus components, such as temperature sensors, can be connected--all in a very accurate subsystem. That's especially needed if you're dealing with lithium-ion chemistry cells.
The IC's built-in Smart Battery System Manager (SBSM) handles battery management and will permit rapid charging of packs. In fact, USAR claims you may see a 60% improvement in charging time over competing approaches. The IC also includes lots of general purpose I/O (GPIO) for system functions.
Usar's IC also embodies the firm's patented Zero-Power power management scheme. Thanks to Zero-Power, the ACPTroller II will always operate in Stop Mode, and wake up gracefully without any data or event losses. What's more, the IC operates continuously between three and five volts, typically sipping less than one µA of current. The company claims that's less than any other embedded controller on the marketplace.
Hot Pluggability
The IC also provides three PS/2 ports for hot-plug connection of external keyboards and mice, as well as pointing devices. Again, the IC powers-down when PS/2 devices are connected and active.
PS/2 mouse input is controlled by USAR's AlphaMouse pointing device manager software. It supports the hot-plug and hot-swap connection of up to three standard two-button and three-button mice. Intellimouse-type devices are also supported, as recommended by Microsoft. Significantly, all mice can operate concurrently.
Internal and external keyboard functions are controlled by the IC's AlphaKey manager module. This software controls both an external keyboard and an internal scanned 8 X 16 key matrix which can support English, Japanese and European keys. A so-called "macro processor" lets you use or define keyboard-invoked ACPI events, or control SMBus devices. It also lets you emulate MouseWheel input, or simply customize scanned matrix key assignments. In addition, you can assign and download custom-defined keyboard macros or procedures that can be invoked through key presses.
The ACPITroller II's SMBus host manages the IC's three SMBus ports. The Zero-Power ports comply with the latest (v1.1) SBS and SMBus specs, including providing cyclic redundancy checking. Using an eight-bit CRC code that's appended to packets, it ensures that bus-transmitted messages don't get lost or discarded if they take hits from noise or RF.
The IC also implements an SBS 1.1-compatible SBSM. It will control a smart charger/smart selector, and also monitors and measures the state and characteristics of a system's batteries. It also supports simultaneous charge/discharge, making decisions as to which batteries to charge and discharge, and when. What's more, Usar's chip will simultaneously charge and discharge without the use of voltage-dropping diode schemes.
Virtual Devices
The ACPITroller II also offers what's called Internal Virtual SMBus Devices, or IVSDs. Modeled on SMBus devices, IVSDs are general-purpose devices that support system tasks. A host can address these devices through the ACPI embedded controller interface in the same way it would address any external device residing on an SMBus port.
Implemented on the chip's shared pins, IVSDs can include port expanders, flat panel digital controls, and a 10-bit resolution A/D converter that offers +/-4 LSB accuracy. By the way, the A/D only draws current when a conversion is requested. IVSDs also enable the chip's GPIO port. The IC also lets you set it up with up to five customizable ACPI General Purpose Events, or GPEs.
Interested? Developer's kits are available. Usar also has a short, well-written "white paper" that describes the chip's advantages in a nicely illustrated format. Get yours, as well as data sheets and docs by contacting Customer Service at USAR Systems, Inc., Customer Support, 568 Broadway, New York, NY 10012. Phone: (212) 226-2042.