System Management Controller: Difference between revisions

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The '''System Management Controller''' ('''SMC''') is a subsystem of [[Intel]] [[Macintosh]] computers. It is similar in function to the older [[System Management Unit|SMU]] or [[Power Management Unit|PMU]] of PowerPC based Macintosh computers.<ref>{{cite web |title=HT2368: About the SMC Firmware Updates |url=http://support.apple.com:80/kb/HT2368?viewlocale=en_US |website=Official Apple Support |archiveurl=https://web.archive.org/web/20081223202919/http://support.apple.com/kb/HT2368?viewlocale=en_US |archivedate=2008-12-23 |url-status=dead }}</ref><ref>{{cite web |title=HT202040: About the SMC Firmware Updates |url=https://support.apple.com/en-us/HT202040 |website=Official Apple Support |publisher= |accessdate=2018-04-28 |archive-date=2021-05-19 |archive-url=https://web.archive.org/web/20210519004618/https://support.apple.com/en-us/HT202040 |url-status=live }}</ref>

The '''SMC''' is an internal sub system introduced by [[Apple]] with the introduction of their new [[Intel]] processor based machines in 2006. It takes over the functions of the SMC. Apple has released updates for this system in order to address power or sleep issues in several resent models[http://search.info.apple.com/index.html?search=Go&lr=lang_en&kword=&khot%20OR%20kcap&news&q=SMC%20update&&type=kbdload|].

==Overview==

The SMC has roles in controlling thermal and power management, battery charging, video mode switching, [[sleep mode|sleep and wake]], [[hibernation (computing)|hibernation]], and [[light-emitting diode|LED]] indicators. It also enables enforcement of the [[macOS]] [[End-user license agreement|End User License]], allowing macOS to identify when it is running on non-Apple hardware.<ref>{{cite podcast |host=[[Randal L. Schwartz|Randal Schwartz]] |date=2010-08-11 |df=mdy |title=VirtualBox |url=https://twit.tv/shows/floss-weekly/episodes/130 |website=[[FLOSS Weekly]] |series=130 |publisher=[[TWiT.tv]] |accessdate=2018-04-28 |archive-date=2018-04-28 |archive-url=https://web.archive.org/web/20180428181223/https://twit.tv/shows/floss-weekly/episodes/130 |url-status=live }}</ref>

The SMC like the SMU before it controls power flow and fan speed. The main objective is to keep the machine running normally with a minimum of noise.

The SMC should not normally need to be reset at all. Doing so however can be useful in [[troubleshooting]] certain issues.

*Failure to turn on

*Failure to recognize internal [[Airport Extreme]] card

*Failure to recognize attached devices (Firewire, USB, etc.)

*Unexpected power off (i.e sudden unexpected lose of power not system shutdown)

*Failure to wake from sleep or unexpected sleep (note this can also be caused by [[operating system]] corruption)

This is due to the fact the SMC may become corrupted over time and not respond properly to certain requests. This sort of corruption can be triggered by a power surge.

==See also==

== Current SMC Updates ==

* [[Embedded controller]] (EC)

{| class="wikitable"

* [[Power management integrated circuit]] (PMIC)

|-

* [[Power Management Unit]] (PMU)

!

* [[System Management Unit]] (SMU)

! Shipping Version

* [[Apple T2]]

! Updated Version

|-

| [[iMac]] Early 2006

| ?

| [http://www.apple.com/support/downloads/imacearly2006smcfirmwareupdate.html 1.1f5]

|-

| [[Mac Mini]] Early 2006

| ?

| [http://www.apple.com/support/downloads/macminiearly2006smcfirmwareupdate.html 1.3f4]

|-

| [[MacBook]] Any

| ?

| [http://www.apple.com/support/downloads/macbooksmcfirmwareupdate11.html 1.4f12]

|-

| [[MacBookPro|MacBook Pro]] 15-inch

| ?

| [http://www.apple.com/support/downloads/macbookpro15inchsmcfirmwareupdate.html 1.2f10]

|-

| [[MacBookPro|MacBook Pro]] 17-inch

| ?

| [http://www.apple.com/support/downloads/macbookpro17inchsmcfirmwareupdate.html 1.5f10]

|}

==References==

{{Mac-stub}}

{{reflist}}

==External links==

{{step|[[System_management_unit|SMU]]|}}

*[https://support.apple.com/kb/HT201518 EFI and SMC firmware updates for Intel-based Macs]

[[Category:Lists of three-character combinations]]

[[Category:Products introduced in 2006]]

[[Category:Macintosh computers]]

[[Category:Apple ComputerInc. hardware]]