Embedded controller: Difference between revisions

Revision as of 17:56, 27 June 2014

Revision as of 18:52, 27 June 2014

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An '''Embeddedembedded Controllercontroller''' ('''EC''') is a special [[microcontroller]] in [[notebookcomputer]]s referredthat to thehandle various control tasks independently of the [[operating system]] takes over.

== Tasks ==

An embedded controller typically has the following tasks:

*Receiving keystroke signals from both the notebook keyboard and other buttons and switches (e.g., power-on button, lid switch)

*Turning the computer on and off

*On and off of the actual computer system

*[[Charge control]] of the [[batteries]]

*Thermal measurement and management including controlling the fans and responding to thermal emergencies

*Measuring the temperature

*Control of the [[fan]] and other cooling

*Placing the actual computer system into a "sleep" mode ([[standby]]) and the reawakening of it (Resume)

*Control any [[LED]]s on the system

*Optionally, remote diagnostics and remediation of a computer.

The embedded controller is always on when power is supplied to the mainboard (from the battery, or external adapter, or +5VSB from a power supply unit).

The actual computer system can communicate with the embedded controller. For one of the following forms of communication is often used:

*[[Advanced Configuration and Power Interface]]

*[[ACPI Embedded Controller]]

*[[SMBus]]

*[[Shared Memory]]

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== Software ==

The Embedded Controller has its own [[RAM]] and almost always its own [[flash ROM]] on which the executable [[software]] is stored. This software is depending on the [[manufacturer]] and often named differently:

*"[[firmware]]", " EC Firmware" "or " Embedded Controller Firmware "

*"EC [[BIOS]]" "or " Embedded Controller BIOS "

*"Micro software"

*"Keyboard BIOS", "Keyboard Controller BIOS" or "KBC BIOS"

Many BIOS updates contain,also inpackage additionupdates to updating the actual BIOS software also updates the embedded controller firmware.

In cases where there is no separate each firmware for BIOS and Embedded Controller, Embedded Controller has the likelyembedded together withcontroller, the actualembedded [[CPU]]controller's sharedfirmware accesswould tobe the single [[flash memory]] ofinside the system. This common access often means the form of communication [[sharedBIOS memory]]ROM.

== Name ==

The name "Keyboard Controller BIOS" comes from the fact that the embedded controller isevolved almost always the task offrom the keyboard controller takesand overoften thestill notebookis keyboard.used Alsoas seena historicallykeyboard thatcontroller. hasEven evolvedtoday, toan theACPI Embeddedembedded Controller,controller whichcommunicates onlywith the earlierCPU keyboardby controllerusing was.the Evensame today,I/O whenports athat ACPIkeyboard embeddedcontrollers controllerused is communicatingin the samepast: wayI/O ([[port]]s 0x62 and 0x66 port) is used, as it was customary for communications with the keyboard controller.

== System architectures ==