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data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Interface" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Interface"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Interface</span> </div> </a> <ul id="toc-Interface-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Data_encoding" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Data_encoding"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Data encoding</span> </div> </a> <button aria-controls="toc-Data_encoding-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Data encoding subsection</span> </button> <ul id="toc-Data_encoding-sublist" class="vector-toc-list"> <li id="toc-Bit_encoding" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Bit_encoding"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Bit encoding</span> </div> </a> <ul id="toc-Bit_encoding-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Data_words" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Data_words"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Data words</span> </div> </a> <ul id="toc-Data_words-sublist" class="vector-toc-list"> <li id="toc-Acknowledge_sequence" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Acknowledge_sequence"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2.1</span> <span>Acknowledge sequence</span> </div> </a> <ul id="toc-Acknowledge_sequence-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> </ul> </li> <li id="toc-Command_structure" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Command_structure"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Command structure</span> </div> </a> <button aria-controls="toc-Command_structure-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Command structure subsection</span> </button> <ul id="toc-Command_structure-sublist" class="vector-toc-list"> <li id="toc-Standby_pulse" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Standby_pulse"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Standby pulse</span> </div> </a> <ul id="toc-Standby_pulse-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Start_header" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Start_header"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Start header</span> </div> </a> <ul id="toc-Start_header-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Device_address" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Device_address"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Device address</span> </div> </a> <ul id="toc-Device_address-sublist" class="vector-toc-list"> <li id="toc-8-bit_addressing" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#8-bit_addressing"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3.1</span> <span>8-bit addressing</span> </div> </a> <ul id="toc-8-bit_addressing-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-12-bit_addressing" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#12-bit_addressing"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3.2</span> <span>12-bit addressing</span> </div> </a> <ul id="toc-12-bit_addressing-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Command_byte" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Command_byte"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.4</span> <span>Command byte</span> </div> </a> <ul id="toc-Command_byte-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Bus_Parasitic_Power" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a 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class="mbox-text"><div class="mbox-text-span"><div class="multiple-issues-text mw-collapsible"><b>This article has multiple issues.</b> Please help <b><a href="/wiki/Special:EditPage/UNI/O" title="Special:EditPage/UNI/O">improve it</a></b> or discuss these issues on the <b><a href="/wiki/Talk:UNI/O" title="Talk:UNI/O">talk page</a></b>. <small><i>(<a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove these messages</a>)</i></small> <div class="mw-collapsible-content"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1251242444"><table class="box-More_footnotes_needed plainlinks metadata ambox ambox-style ambox-More_footnotes_needed" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a4/Text_document_with_red_question_mark.svg/40px-Text_document_with_red_question_mark.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a4/Text_document_with_red_question_mark.svg/60px-Text_document_with_red_question_mark.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a4/Text_document_with_red_question_mark.svg/80px-Text_document_with_red_question_mark.svg.png 2x" data-file-width="48" data-file-height="48" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article includes a list of <a href="/wiki/Wikipedia:Citing_sources#General_references" title="Wikipedia:Citing sources">general references</a>, but <b>it lacks sufficient corresponding <a href="/wiki/Wikipedia:Citing_sources#Inline_citations" title="Wikipedia:Citing sources">inline citations</a></b>.<span class="hide-when-compact"> Please help to <a href="/wiki/Wikipedia:WikiProject_Reliability" title="Wikipedia:WikiProject Reliability">improve</a> this article by <a href="/wiki/Wikipedia:When_to_cite" title="Wikipedia:When to cite">introducing</a> more precise citations.</span> <span class="date-container"><i>(<span class="date">October 2009</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1251242444"><table class="box-More_citations_needed plainlinks metadata ambox ambox-content ambox-Refimprove" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><a href="/wiki/File:Question_book-new.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png" decoding="async" width="50" height="39" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/75px-Question_book-new.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/100px-Question_book-new.svg.png 2x" data-file-width="512" data-file-height="399" /></a></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article <b>needs additional citations for <a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability">verification</a></b>.<span class="hide-when-compact"> Please help <a href="/wiki/Special:EditPage/UNI/O" title="Special:EditPage/UNI/O">improve this article</a> by <a href="/wiki/Help:Referencing_for_beginners" title="Help:Referencing for beginners">adding citations to reliable sources</a>. Unsourced material may be challenged and removed.<br /><small><span class="plainlinks"><i>Find sources:</i> <a rel="nofollow" class="external text" href="https://www.google.com/search?as_eq=wikipedia&q=%22UNI%2FO%22">"UNI/O"</a> – <a rel="nofollow" class="external text" href="https://www.google.com/search?tbm=nws&q=%22UNI%2FO%22+-wikipedia&tbs=ar:1">news</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?&q=%22UNI%2FO%22&tbs=bkt:s&tbm=bks">newspapers</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?tbs=bks:1&q=%22UNI%2FO%22+-wikipedia">books</a> <b>·</b> <a rel="nofollow" class="external text" href="https://scholar.google.com/scholar?q=%22UNI%2FO%22">scholar</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.jstor.org/action/doBasicSearch?Query=%22UNI%2FO%22&acc=on&wc=on">JSTOR</a></span></small></span> <span class="date-container"><i>(<span class="date">October 2009</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> </div> </div><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Example_UNIO_schematic_with_4_slaves.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/8c/Example_UNIO_schematic_with_4_slaves.svg/300px-Example_UNIO_schematic_with_4_slaves.svg.png" decoding="async" width="300" height="318" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/8c/Example_UNIO_schematic_with_4_slaves.svg/450px-Example_UNIO_schematic_with_4_slaves.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/8c/Example_UNIO_schematic_with_4_slaves.svg/600px-Example_UNIO_schematic_with_4_slaves.svg.png 2x" data-file-width="650" data-file-height="690" /></a><figcaption>UNI/O bus example: single master and four slaves</figcaption></figure> <figure typeof="mw:File/Thumb"><a href="/wiki/File:UNIO_WLCSP_and_SOT23_Device_on_Penny.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/52/UNIO_WLCSP_and_SOT23_Device_on_Penny.jpg/200px-UNIO_WLCSP_and_SOT23_Device_on_Penny.jpg" decoding="async" width="200" height="203" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/52/UNIO_WLCSP_and_SOT23_Device_on_Penny.jpg/300px-UNIO_WLCSP_and_SOT23_Device_on_Penny.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/52/UNIO_WLCSP_and_SOT23_Device_on_Penny.jpg/400px-UNIO_WLCSP_and_SOT23_Device_on_Penny.jpg 2x" data-file-width="546" data-file-height="553" /></a><figcaption>Example UNI/O devices in <a href="/wiki/SOT-23" class="mw-redirect" title="SOT-23">SOT-23</a> and <a href="/wiki/Chip_scale_package" class="mw-redirect" title="Chip scale package">wafer level chip scale packages</a> sitting on the face of a <a href="/wiki/U.S._penny" class="mw-redirect" title="U.S. penny">U.S. penny</a></figcaption></figure> <p>The <b>UNI/O bus</b> <span class="rt-commentedText nowrap"><span class="IPA nopopups noexcerpt" lang="en-fonipa"><a href="/wiki/Help:IPA/English" title="Help:IPA/English">/<span style="border-bottom:1px dotted"><span title="/ˌ/: secondary stress follows">ˌ</span><span title="/juː/: 'u' in 'cute'">juː</span><span title="'n' in 'nigh'">n</span><span title="/i/: 'y' in 'happy'">i</span><span title="/ˈ/: primary stress follows">ˈ</span><span title="/oʊ/: 'o' in 'code'">oʊ</span></span>/</a></span></span> is an <a href="/wiki/Asynchronous_serial_communication" title="Asynchronous serial communication">asynchronous</a> <a href="/wiki/Serial_communications" class="mw-redirect" title="Serial communications">serial</a> <a href="/wiki/Bus_(computing)" title="Bus (computing)">bus</a> created by <a href="/wiki/Microchip_Technology" title="Microchip Technology">Microchip Technology</a> for low speed communication in <a href="/wiki/Embedded_system" title="Embedded system">embedded systems</a>.<sup id="cite_ref-UNI/O_Bus_Specification_1-0" class="reference"><a href="#cite_note-UNI/O_Bus_Specification-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> The bus uses a <a href="/wiki/Master/slave_(technology)" class="mw-redirect" title="Master/slave (technology)">master/slave</a> configuration, requiring one <a href="/wiki/Signal_(electronics)" class="mw-redirect" title="Signal (electronics)">signal</a> to pass <a href="/wiki/Data" title="Data">data</a> between devices. The first devices supporting the UNI/O bus were released in May 2008. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Interface">Interface</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=1" title="Edit section: Interface"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The UNI/O bus requires one logic signal: </p> <ul><li>SCIO — Serial Clock, Data Input/Output<sup id="cite_ref-UNI/O_EEPROM_Family_Datasheet_2-0" class="reference"><a href="#cite_note-UNI/O_EEPROM_Family_Datasheet-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup></li></ul> <p>Only one master device is allowed per bus, but multiple slave devices can be connected to a single UNI/O bus. Individual slaves are selected through an 8-bit to 12-bit address included in the <a href="/wiki/Overhead_information" class="mw-redirect" title="Overhead information">command overhead</a>. </p><p>Both master and slave devices use a <a href="/wiki/Three-state_logic" title="Three-state logic">tri-stateable</a>, <a href="/wiki/Push%E2%80%93pull_output" title="Push–pull output">push-pull</a> <a href="/wiki/I/O" class="mw-redirect" title="I/O">I/O</a> pin to connect to SCIO, with the pin being placed in a <a href="/wiki/High_impedance" title="High impedance">high impedance</a> state when not driving the bus. Because push-pull outputs are used, the output driver on slave devices is <a href="/wiki/Current_limiting" title="Current limiting">current-limited</a> to prevent high system <a href="/wiki/Electric_current" title="Electric current">currents</a> from occurring during bus collisions. </p><p>The idle state of the UNI/O bus is <a href="/wiki/Logic_level" title="Logic level">logic high</a>. A pull-up resistor can be used to ensure the bus remains idle when no device is driving SCIO, but is not required for operation.<sup id="cite_ref-AN1194_3-0" class="reference"><a href="#cite_note-AN1194-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Data_encoding">Data encoding</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=2" title="Edit section: Data encoding"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Bit_encoding">Bit encoding</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=3" title="Edit section: Bit encoding"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Example_UNIO_bit_values_showing_Manchester_encoding.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/41/Example_UNIO_bit_values_showing_Manchester_encoding.svg/200px-Example_UNIO_bit_values_showing_Manchester_encoding.svg.png" decoding="async" width="200" height="163" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/41/Example_UNIO_bit_values_showing_Manchester_encoding.svg/300px-Example_UNIO_bit_values_showing_Manchester_encoding.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/41/Example_UNIO_bit_values_showing_Manchester_encoding.svg/400px-Example_UNIO_bit_values_showing_Manchester_encoding.svg.png 2x" data-file-width="194" data-file-height="158" /></a><figcaption>UNI/O bit encoding examples</figcaption></figure> <p>Clock and data signals are combined and communicated on the bus through <a href="/wiki/Manchester_code" title="Manchester code">Manchester encoding</a>. This means that each <a href="/wiki/Bit" title="Bit">data bit</a> is transmitted in a fixed amount of time (called the "<a href="/w/index.php?title=Bit_period&action=edit&redlink=1" class="new" title="Bit period (page does not exist)">bit period</a>"). </p><p>The UNI/O specification places certain rules on the bit period: </p> <ul><li>It is determined by the master. <ul><li>Slaves are required to <a href="/wiki/Synchronize" class="mw-redirect" title="Synchronize">synchronize</a> with the master to <a href="/wiki/Clock_recovery" title="Clock recovery">recover</a> the bit period during the <a href="#Start_Header">start header</a>.</li></ul></li> <li>It can be within <a href="/wiki/Microsecond" title="Microsecond">10 μs</a> and 100 μs (corresponding to a <a href="/wiki/Bit_rate" title="Bit rate">bit rate</a> of 100 kbit/s to 10 kbit/s, respectively).</li> <li>It is only required to be fixed within a single bus operation (for new bus operations, the master can choose a different bit period).</li></ul> <p>In accordance with Manchester encoding, the bit value is defined by a signal transition in the middle of the bit period. UNI/O uses the <a href="/wiki/Manchester_code#Conventions_for_representation_of_data" title="Manchester code">IEEE 802.3 convention</a> for defining <b>0</b> and <b>1</b> values: </p> <ul><li>A <i>high-to-low</i> transition signifies a <b>0</b>.</li> <li>A <i>low-to-high</i> transition signifies a <b>1</b>.</li></ul> <p>Bit periods occur back-to-back, with no delay between bit periods allowed. </p> <div class="mw-heading mw-heading3"><h3 id="Data_words">Data words</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=4" title="Edit section: Data words"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:UNIO_data_byte_and_acknowledge_sequence_diagram.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c3/UNIO_data_byte_and_acknowledge_sequence_diagram.svg/350px-UNIO_data_byte_and_acknowledge_sequence_diagram.svg.png" decoding="async" width="350" height="84" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c3/UNIO_data_byte_and_acknowledge_sequence_diagram.svg/525px-UNIO_data_byte_and_acknowledge_sequence_diagram.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c3/UNIO_data_byte_and_acknowledge_sequence_diagram.svg/700px-UNIO_data_byte_and_acknowledge_sequence_diagram.svg.png 2x" data-file-width="528" data-file-height="127" /></a><figcaption>UNI/O data byte and acknowledge sequence</figcaption></figure> <p>UNI/O uses 8-bit <a href="/wiki/Data_word" class="mw-redirect" title="Data word">data words</a> for communication. Bytes are transmitted <a href="/wiki/Most_significant_bit" class="mw-redirect" title="Most significant bit">msb</a> first. </p> <div class="mw-heading mw-heading4"><h4 id="Acknowledge_sequence">Acknowledge sequence</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=5" title="Edit section: Acknowledge sequence"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>To facilitate <a href="/wiki/Error_detection" class="mw-redirect" title="Error detection">error detection</a>, a 2-bit wide "<a href="/wiki/Acknowledgement_(data_networks)" title="Acknowledgement (data networks)">acknowledge</a> sequence" is appended to the end of every data byte transmitted. The first bit is called the "master acknowledge" (shortened to "MAK") and is always generated by the master. The second bit, called the "slave acknowledge" (shortened to "SAK"), is always generated by the slave. </p><p>The MAK bit is used in the following manner: </p> <ul><li>The master transmits a <b>1</b> bit (a <i>MAK</i>) to indicate to the slave that the bus operation will be continued.</li> <li>The master transmits a <b>0</b> bit (a <i>NoMAK</i>) to indicate that the preceding byte was the last byte for that bus operation.</li></ul> <p>The SAK bit is used in the following manner: </p> <ul><li>Once a full device address has been transmitted (and a valid slave has been selected), if the previous data byte and subsequent MAK bit were received correctly, the slave transmits a <b>1</b> bit (a <i>SAK</i>).</li> <li>If an error occurs, the slave automatically shuts down and ignores further communication until a standby pulse is received. In this scenario, nothing will be transmitted during the SAK bit period. This missing transition can be detected by the master and is considered a <i>NoSAK</i> bit.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Command_structure">Command structure</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=6" title="Edit section: Command structure"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Standby_pulse">Standby pulse</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=7" title="Edit section: Standby pulse"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>UNI/O defines a signal pulse, called the "standby pulse", that can be generated by the master to force slave devices into a reset state (referred to as "standby mode"). To generate a standby pulse, the master must drive the bus to a logic high for a minimum of 600 μs. </p><p>A standby pulse is required to be generated under certain conditions: </p> <ul><li>Before initiating a command when selecting a new device (including after a <a href="/wiki/Power-on_reset" title="Power-on reset">POR</a>/BOR event)</li> <li>After an error is detected</li></ul> <p>If a command is completed without error, a new command to the same device can be initiated without generating a standby pulse. </p> <div class="mw-heading mw-heading3"><h3 id="Start_header">Start header</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=8" title="Edit section: Start header"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:UNIO_Start_Header_Timing_Diagram.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/25/UNIO_Start_Header_Timing_Diagram.svg/400px-UNIO_Start_Header_Timing_Diagram.svg.png" decoding="async" width="400" height="127" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/25/UNIO_Start_Header_Timing_Diagram.svg/600px-UNIO_Start_Header_Timing_Diagram.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/25/UNIO_Start_Header_Timing_Diagram.svg/800px-UNIO_Start_Header_Timing_Diagram.svg.png 2x" data-file-width="711" data-file-height="225" /></a><figcaption>UNI/O start header</figcaption></figure> <p>The start header is a special byte sequence defined by the UNI/O specification, and is used to initiate a new command. The start header consists of the following elements: </p> <ul><li>The master drives the bus low for a minimum of 5 μs.</li> <li>The master outputs a <b>0x55</b> data byte. <ul><li>Slave devices measure the time necessary to receive the <b>0x55</b> byte by counting signal transitions. This time is then used by the slaves to determine the bit period and synchronize with the master.</li></ul></li> <li>The master outputs a <b>1</b> for the MAK bit.</li> <li>The slave devices <i>do not</i> respond during the SAK bit following the start header. This is to avoid bus collisions which would occur of all slave devices tried to respond at the same time.</li></ul> <div class="mw-heading mw-heading3"><h3 id="Device_address">Device address</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=9" title="Edit section: Device address"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>After the start header has been transmitted, the master must transmit a device address to select the desired slave device for the current operation. Once the device address has been sent, any slave device with an address different from that specified is required to shut down and ignore all further communication until a standby pulse is received. </p><p>UNI/O allows for both 8-bit and 12-bit device addresses. 8-bit addressing offers better data throughput due to less command overhead, while 12-bit addressing allows for more slaves with a common family code to exist on a single bus. When a slave device is designed, the designer must choose which addressing scheme to use. </p> <div class="mw-heading mw-heading4"><h4 id="8-bit_addressing">8-bit addressing</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=10" title="Edit section: 8-bit addressing"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>For 8-bit addressing, the entire device address is transmitted in a single byte. The most significant 4 bits indicate the "family code", which is defined by Microchip in the UNI/O bus specification. The least significant 4 bits indicate the device code. The device code allows multiple slave devices with a common family code to be used on the same bus. The device code can be fixed for a given slave or customizable by the user. Choosing a device code and how it can be customized (if necessary) are the responsibilities of the slave device designer. </p><p>The current family codes for 8-bit devices, as of November 22, 2009,<sup id="cite_ref-UNI/O_Bus_Specification_1-1" class="reference"><a href="#cite_note-UNI/O_Bus_Specification-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> are as follows: </p> <table class="wikitable"> <tbody><tr> <th>Family Code </th> <th>Description </th></tr> <tr> <td align="center">′<b>0000</b>′ </td> <td>Reserved </td></tr> <tr> <td align="center">′<b>0011</b>′ </td> <td>Display Controllers </td></tr> <tr> <td align="center">′<b>0100</b>′ </td> <td><a href="/wiki/Port_expander" title="Port expander">I/O port expanders</a> </td></tr> <tr> <td align="center">′<b>1000</b>′ </td> <td><a href="/wiki/Frequency" title="Frequency">Frequency</a>/<a href="/wiki/Quadrature_encoder" class="mw-redirect" title="Quadrature encoder">Quadrature</a>/<a href="/wiki/Pulse-width_modulation" title="Pulse-width modulation">PWM</a> encoders, <a href="/wiki/Real-time_clock" title="Real-time clock">real-time clocks</a> </td></tr> <tr> <td align="center">′<b>1001</b>′ </td> <td><a href="/wiki/Temperature_Sensor" class="mw-redirect" title="Temperature Sensor">Temperature sensors</a> </td></tr> <tr> <td align="center">′<b>1010</b>′ </td> <td><a href="/wiki/EEPROM" title="EEPROM">EEPROMs</a> </td></tr> <tr> <td align="center">′<b>1011</b>′ </td> <td>Encryption/Authentication Devices </td></tr> <tr> <td align="center">′<b>1100</b>′ </td> <td>DC/DC Converters </td></tr> <tr> <td align="center">′<b>1101</b>′ </td> <td><a href="/wiki/A/D_converter" class="mw-redirect" title="A/D converter">A/D converters</a> </td></tr> <tr> <td align="center">′<b>1111</b>′ </td> <td>12-bit addressable devices </td></tr></tbody></table> <div class="mw-heading mw-heading4"><h4 id="12-bit_addressing">12-bit addressing</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=11" title="Edit section: 12-bit addressing"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>For 12-bit addressing, the device address is sent in two bytes. The most significant 4 bits of the first byte (which would correspond to the family code in 8-bit addressing), are set to ′<b>1111</b>′. The next 4 bits are the family code for the 12-bit address, and the second byte of the address is an 8-bit wide device code. The device code follows the same guidelines for definition as with 8-bit addressing. </p><p>Because the specified slave device is not selected until both bytes of the device address have been received, a NoSAK will occur during the acknowledge sequence following the first device address byte. </p><p>The current family codes for 12-bit devices, as of November 22, 2009,<sup id="cite_ref-UNI/O_Bus_Specification_1-2" class="reference"><a href="#cite_note-UNI/O_Bus_Specification-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> are as follows: </p> <table class="wikitable"> <tbody><tr> <th>Family Code </th> <th>Description </th></tr> <tr> <td align="center">′<b>0000</b>′ </td> <td>Reserved </td></tr> <tr> <td align="center">′<b>1111</b>′ </td> <td>Reserved </td></tr></tbody></table> <div class="mw-heading mw-heading3"><h3 id="Command_byte">Command byte</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=12" title="Edit section: Command byte"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>After the master has transmitted the device address and selected an individual slave, the master must transmit the 8-bit value for the specific command to be executed by the slave. The available commands are determined by the designer of each slave device, and will vary from slave to slave, e.g. a serial EEPROM will likely have different commands than a temperature sensor. The slave device designer will also determine if and how many data bytes are necessary for the execution of a command. If any data bytes are necessary, they are transmitted by either the master or the slave (dictated by the command type) after the command byte. </p><p>Communication will continue until either the master transmits a <b>0</b> (NoMAK) during the acknowledge sequence, or an error occurs. Assuming no errors occur, this means that commands can continue indefinitely if the master chooses. </p><p><br /> </p> <div class="mw-heading mw-heading2"><h2 id="Bus_Parasitic_Power">Bus Parasitic Power</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=13" title="Edit section: Bus Parasitic Power"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Some UNI/O Parts can be powered from the bus, eliminating the need for a dedicated supply voltage/wire.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=14" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-UNI/O_Bus_Specification-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-UNI/O_Bus_Specification_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-UNI/O_Bus_Specification_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-UNI/O_Bus_Specification_1-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation cs2"><a rel="nofollow" class="external text" href="http://ww1.microchip.com/downloads/en/DeviceDoc/22076D.pdf"><i>UNI/O Bus Specification</i></a> <span class="cs1-format">(PDF)</span><span class="reference-accessdate">, retrieved <span class="nowrap">2009-11-22</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=UNI%2FO+Bus+Specification&rft_id=http%3A%2F%2Fww1.microchip.com%2Fdownloads%2Fen%2FDeviceDoc%2F22076D.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUNI%2FO" class="Z3988"></span></span> </li> <li id="cite_note-UNI/O_EEPROM_Family_Datasheet-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-UNI/O_EEPROM_Family_Datasheet_2-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="http://ww1.microchip.com/downloads/en/DeviceDoc/22067E.pdf"><i>1K-16K UNI/O Serial EEPROM Family Data Sheet</i></a> <span class="cs1-format">(PDF)</span><span class="reference-accessdate">, retrieved <span class="nowrap">2009-10-21</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=1K-16K+UNI%2FO+Serial+EEPROM+Family+Data+Sheet&rft_id=http%3A%2F%2Fww1.microchip.com%2Fdownloads%2Fen%2FDeviceDoc%2F22067E.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUNI%2FO" class="Z3988"></span></span> </li> <li id="cite_note-AN1194-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-AN1194_3-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="http://ww1.microchip.com/downloads/en/AppNotes/01194B.pdf"><i>AN1194, Recommended Usage of Microchip UNI/O Bus-Compatible Serial EEPROMs</i></a> <span class="cs1-format">(PDF)</span><span class="reference-accessdate">, retrieved <span class="nowrap">2009-10-21</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=AN1194%2C+Recommended+Usage+of+Microchip+UNI%2FO+Bus-Compatible+Serial+EEPROMs&rft_id=http%3A%2F%2Fww1.microchip.com%2Fdownloads%2Fen%2FAppNotes%2F01194B.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUNI%2FO" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.microchip.com/en-us/products/memory/serial-eeprom/single-wire-and-uniobus-serial-eeproms">Single-Wire and UNI/O® Bus Serial EEPROMs</a></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://ww1.microchip.com/downloads/en/Appnotes/01213B.pdf">"Powering a UNI/O® Bus Device Through SCIO"</a> <span class="cs1-format">(PDF)</span><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-01-27</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Powering+a+UNI%2FO%C2%AE+Bus+Device+Through+SCIO&rft_id=https%3A%2F%2Fww1.microchip.com%2Fdownloads%2Fen%2FAppnotes%2F01213B.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUNI%2FO" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://ww1.microchip.com/downloads/en/DeviceDoc/22199b.pdf">"UNI/O® Bus Parasitic Power Demo Board"</a> <span class="cs1-format">(PDF)</span><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-01-27</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=UNI%2FO%C2%AE+Bus+Parasitic+Power+Demo+Board&rft_id=https%3A%2F%2Fww1.microchip.com%2Fdownloads%2Fen%2FDeviceDoc%2F22199b.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AUNI%2FO" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=UNI/O&action=edit&section=15" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="http://ww1.microchip.com/downloads/en/devicedoc/22076d.pdf">UNI/O Bus Specification</a> - Microchip</li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist 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.hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Technical_and_de_facto_standards_for_wired_computer_buses" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output 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abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Computer_bus" title="Template:Computer bus"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Computer_bus" title="Template talk:Computer bus"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Computer_bus" title="Special:EditPage/Template:Computer bus"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Technical_and_de_facto_standards_for_wired_computer_buses" style="font-size:114%;margin:0 4em"><a href="/wiki/Technical_standard" title="Technical standard">Technical</a> and <a href="/wiki/De_facto_standard" title="De facto standard"><i>de facto</i> standards</a> for <a href="/wiki/Wired_communication" title="Wired communication">wired</a> <a href="/wiki/Bus_(computing)" title="Bus (computing)">computer buses</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">General</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/System_bus" title="System bus">System bus</a></li> <li><a href="/wiki/Front-side_bus" title="Front-side bus">Front-side bus</a></li> <li><a href="/wiki/Back-side_bus" title="Back-side bus">Back-side bus</a></li> <li><a href="/wiki/Daisy_chain_(electrical_engineering)" title="Daisy chain (electrical engineering)">Daisy chain</a></li> <li><a href="/wiki/Control_bus" title="Control bus">Control bus</a></li> <li><a href="/wiki/Address_bus" class="mw-redirect" title="Address bus">Address bus</a></li> <li><a href="/wiki/Bus_contention" title="Bus contention">Bus contention</a></li> <li><a href="/wiki/Bus_mastering" title="Bus mastering">Bus mastering</a></li> <li><a href="/wiki/Network_on_a_chip" title="Network on a chip">Network on a chip</a></li> <li><a href="/wiki/Plug_and_play" title="Plug and play">Plug and play</a></li> <li><a href="/wiki/List_of_interface_bit_rates#Computer_buses" title="List of interface bit rates">List of bus bandwidths</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Standards</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/SS-50_bus" title="SS-50 bus">SS-50 bus</a></li> <li><a href="/wiki/S-100_bus" title="S-100 bus">S-100 bus</a></li> <li><a href="/wiki/Multibus" title="Multibus">Multibus</a></li> <li><a href="/wiki/Unibus" title="Unibus">Unibus</a></li> <li><a href="/wiki/VAXBI_bus" title="VAXBI bus">VAXBI</a></li> <li><a href="/wiki/MBus_(SPARC)" title="MBus (SPARC)">MBus</a></li> <li><a href="/wiki/STD_Bus" title="STD Bus">STD Bus</a></li> <li><a href="/wiki/System_Management_Bus" title="System Management Bus">SMBus</a></li> <li><a href="/wiki/Q-Bus" title="Q-Bus">Q-Bus</a></li> <li><a href="/wiki/Europe_Card_Bus" title="Europe Card Bus">Europe Card Bus</a></li> <li><a href="/wiki/Industry_Standard_Architecture" title="Industry Standard Architecture">ISA</a></li> <li><a href="/wiki/STEbus" title="STEbus">STEbus</a></li> <li><a href="/wiki/Amiga_Zorro_II" title="Amiga Zorro II">Zorro II</a></li> <li><a href="/wiki/Amiga_Zorro_III" title="Amiga Zorro III">Zorro III</a></li> <li><a href="/wiki/Computer_Automated_Measurement_and_Control" title="Computer Automated Measurement and Control">CAMAC</a></li> <li><a href="/wiki/FASTBUS" title="FASTBUS">FASTBUS</a></li> <li><a href="/wiki/Low_Pin_Count" title="Low Pin Count">LPC</a></li> <li><a href="/wiki/HP_Precision_Bus" title="HP Precision Bus">HP Precision Bus</a></li> <li><a href="/wiki/Extended_Industry_Standard_Architecture" title="Extended Industry Standard Architecture">EISA</a></li> <li><a href="/wiki/VMEbus" title="VMEbus">VME</a></li> <li><a href="/wiki/VME_eXtensions_for_Instrumentation" title="VME eXtensions for Instrumentation">VXI</a></li> <li><a href="/wiki/VXS" title="VXS">VXS</a></li> <li><a href="/wiki/VPX" title="VPX">VPX</a></li> <li><a href="/wiki/NuBus" title="NuBus">NuBus</a></li> <li><a href="/wiki/TURBOchannel" title="TURBOchannel">TURBOchannel</a></li> <li><a href="/wiki/Micro_Channel_architecture" title="Micro Channel architecture">MCA</a></li> <li><a href="/wiki/SBus" title="SBus">SBus</a></li> <li><a href="/wiki/VESA_Local_Bus" title="VESA Local Bus">VLB</a></li> <li><a href="/wiki/GSC_bus" title="GSC bus">HP GSC bus</a></li> <li><a href="/wiki/InfiniBand" title="InfiniBand">InfiniBand</a></li> <li><a href="/wiki/Ethernet" title="Ethernet">Ethernet</a></li> <li><a href="/wiki/Ultra_Port_Architecture" title="Ultra Port Architecture">UPA</a></li> <li><a href="/wiki/Peripheral_Component_Interconnect" title="Peripheral Component Interconnect">PCI</a></li> <li><a href="/wiki/PCI-X" title="PCI-X">PCI Extended (PCI-X)</a></li> <li><a href="/wiki/PCI_eXtensions_for_Instrumentation" title="PCI eXtensions for Instrumentation">PXI</a></li> <li><a href="/wiki/PCI_Express" title="PCI Express">PCI Express (PCIe)</a></li> <li><a href="/wiki/Accelerated_Graphics_Port" title="Accelerated Graphics Port">AGP</a></li> <li><a href="/wiki/Compute_Express_Link" title="Compute Express Link">Compute Express Link (CXL)</a></li> <li><a href="/wiki/Direct_Media_Interface" title="Direct Media Interface">Direct Media Interface (DMI)</a></li> <li><a href="/wiki/RapidIO" title="RapidIO">RapidIO</a></li> <li><a href="/wiki/Intel_QuickPath_Interconnect" title="Intel QuickPath Interconnect">Intel QuickPath Interconnect</a></li> <li><a href="/wiki/NVLink" title="NVLink">NVLink</a></li> <li><a href="/wiki/HyperTransport" title="HyperTransport">HyperTransport</a> <ul><li><a href="/wiki/Infinity_Fabric" class="mw-redirect" title="Infinity Fabric">Infinity Fabric</a></li></ul></li> <li><a href="/wiki/Intel_Ultra_Path_Interconnect" title="Intel Ultra Path Interconnect">Intel Ultra Path Interconnect</a></li> <li><a href="/wiki/Coherent_Accelerator_Processor_Interface" title="Coherent Accelerator Processor Interface">Coherent Accelerator Processor Interface (CAPI)</a></li> <li><a href="/wiki/SpaceWire" title="SpaceWire">SpaceWire</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Storage</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ST-506/ST-412" title="ST-506/ST-412">ST-506</a></li> <li><a href="/wiki/Enhanced_Small_Disk_Interface" title="Enhanced Small Disk Interface">ESDI</a></li> <li><a href="/wiki/Intelligent_Peripheral_Interface" title="Intelligent Peripheral Interface">IPI</a></li> <li><a href="/wiki/Storage_Module_Device" title="Storage Module Device">SMD</a></li> <li><a href="/wiki/Parallel_ATA" title="Parallel ATA">Parallel ATA (PATA)</a></li> <li><a href="/wiki/Bus_and_Tag" title="Bus and Tag">Bus and Tag</a></li> <li><a href="/wiki/Digital_Storage_Systems_Interconnect" title="Digital Storage Systems Interconnect">DSSI</a></li> <li><a href="/wiki/HIPPI" title="HIPPI">HIPPI</a></li> <li><a href="/wiki/SATA" title="SATA">Serial ATA (SATA)</a></li> <li><a href="/wiki/SCSI" title="SCSI">SCSI</a> <ul><li><a href="/wiki/Parallel_SCSI" title="Parallel SCSI">Parallel</a></li> <li><a href="/wiki/Serial_Attached_SCSI" title="Serial Attached SCSI">SAS</a></li></ul></li> <li><a href="/wiki/ESCON" title="ESCON">ESCON</a></li> <li><a href="/wiki/Fibre_Channel" title="Fibre Channel">Fibre Channel</a></li> <li><a href="/wiki/Serial_Storage_Architecture" title="Serial Storage Architecture">SSA</a></li> <li><a href="/wiki/SATA_Express" title="SATA Express">SATAe</a></li> <li>PCI Express (via <a href="/wiki/Advanced_Host_Controller_Interface" title="Advanced Host Controller Interface">AHCI</a> or <a href="/wiki/NVM_Express" title="NVM Express">NVMe</a> logical device interface)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Peripheral</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Apple_Desktop_Bus" title="Apple Desktop Bus">Apple Desktop Bus</a></li> <li><a href="/wiki/Atari_SIO" title="Atari SIO">Atari SIO</a></li> <li><a href="/wiki/Digital_Control_Bus" title="Digital Control Bus">DCB</a></li> <li><a href="/wiki/Commodore_bus" title="Commodore bus">Commodore bus</a></li> <li><a href="/wiki/HP-IL" title="HP-IL">HP-IL</a></li> <li><a href="/wiki/HIL_bus" title="HIL bus">HIL</a></li> <li><a href="/wiki/MIDI" title="MIDI">MIDI</a></li> <li><a href="/wiki/RS-232" title="RS-232">RS-232</a></li> <li><a href="/wiki/RS-422" title="RS-422">RS-422</a></li> <li><a href="/wiki/RS-423" title="RS-423">RS-423</a></li> <li><a href="/wiki/RS-485" title="RS-485">RS-485</a></li> <li><a href="/wiki/Lightning_(connector)" title="Lightning (connector)">Lightning</a></li> <li><a href="/wiki/DMX512#DMX512-A" title="DMX512">DMX512-A</a></li> <li><a href="/wiki/IEEE-488" class="mw-redirect" title="IEEE-488">IEEE-488 (GPIB)</a></li> <li><a href="/wiki/IEEE_1284" title="IEEE 1284">IEEE-1284 (parallel port)</a></li> <li><a href="/wiki/IEEE_1394" title="IEEE 1394">IEEE-1394 (FireWire)</a></li> <li><a class="mw-selflink selflink">UNI/O</a></li> <li><a href="/wiki/1-Wire" title="1-Wire">1-Wire</a></li> <li><a href="/wiki/I%C2%B2C" title="I²C">I²C</a> (<a href="/wiki/ACCESS.bus" title="ACCESS.bus">ACCESS.bus</a>, <a href="/wiki/Power_Management_Bus" title="Power Management Bus">PMBus</a>, <a href="/wiki/System_Management_Bus" title="System Management Bus">SMBus</a>)</li> <li><a href="/wiki/I3C_(bus)" title="I3C (bus)">I3C</a></li> <li><a href="/wiki/Serial_Peripheral_Interface" title="Serial Peripheral Interface">SPI</a></li> <li><a href="/wiki/IEC_61030" title="IEC 61030">D²B</a></li> <li><a href="/wiki/Parallel_SCSI" title="Parallel SCSI">Parallel SCSI</a></li> <li><a href="/wiki/Profibus" title="Profibus">Profibus</a></li> <li><a href="/wiki/USB" title="USB">USB</a></li> <li><a href="/wiki/Camera_Link" title="Camera Link">Camera Link</a></li> <li><a href="/wiki/PCI_Express#PCI_Express_External_Cabling" title="PCI Express">External PCIe</a></li> <li><a href="/wiki/Thunderbolt_(interface)" title="Thunderbolt (interface)">Thunderbolt</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Audio</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ADAT_Lightpipe" title="ADAT Lightpipe">ADAT Lightpipe</a></li> <li><a href="/wiki/AES3" title="AES3">AES3</a></li> <li><a href="/wiki/Intel_High_Definition_Audio" title="Intel High Definition Audio">Intel HD Audio</a></li> <li><a href="/wiki/I%C2%B2S" title="I²S">I²S</a></li> <li><a href="/wiki/MADI" title="MADI">MADI</a></li> <li><a href="/wiki/McASP" title="McASP">McASP</a></li> <li><a href="/wiki/S/PDIF" title="S/PDIF">S/PDIF</a></li> <li><a href="/wiki/TOSLINK" title="TOSLINK">TOSLINK</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Portable</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/PC_Card" title="PC Card">PC Card</a></li> <li><a href="/wiki/ExpressCard" title="ExpressCard">ExpressCard</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Embedded</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Multidrop_bus" title="Multidrop bus">Multidrop bus</a></li> <li><a href="/wiki/CoreConnect" title="CoreConnect">CoreConnect</a></li> <li><a href="/wiki/Advanced_Microcontroller_Bus_Architecture" title="Advanced Microcontroller Bus Architecture">AMBA</a> (<a href="/wiki/Advanced_eXtensible_Interface" title="Advanced eXtensible Interface">AXI</a>)</li> <li><a href="/wiki/Wishbone_(computer_bus)" title="Wishbone (computer bus)">Wishbone</a></li> <li><a href="/wiki/SLIMbus" title="SLIMbus">SLIMbus</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div><small>Interfaces are listed by their speed in the (roughly) ascending order, so the interface at the end of each section should be the fastest.</small><br /><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" 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