Serial Peripheral Interface: Difference between revisions

Revision as of 14:04, 27 September 2024

Revision as of 14:24, 27 September 2024

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'''Serial Peripheral Interface''' ('''SPI''') is a [[de facto standard|''de facto'' standard]] (with many [[#Variations|variants]]) for [[Comparison of synchronous and asynchronous signalling|synchronous]] [[serial communication]], used primarily in [[embedded systems]] for short-distance [[wired communication]] between [[integrated circuits]].

SPI usesfollows a [[master–slave (technology)|master–slave architecture]], described here with the terms "main" and "sub",{{NoteTag|The {{slink||Alternative terminology}} section gives more details on proposed alternative terminology. See [[Talk:Serial Peripheral Interface#Terminology|the talk page]] for an ongoing discussion.}} <ref name=":0">{{Cite web |last=Dhaker |first=Piyu |date=2018 |title=Introduction to SPI Interface |url=https://www.analog.com/en/analog-dialogue/articles/introduction-to-spi-interface.html |url-status=live |archive-url=https://web.archive.org/web/20230525152752/https://www.analog.com/en/analog-dialogue/articles/introduction-to-spi-interface.html |archive-date=2023-05-25 |access-date=2023-07-21 |website=[[Analog Dialogue]]}}</ref> called ''main–sub'' herein, {{NoteTag|Using main and sub maintains the same initial letters to remain in sync with the line names. For example MISO could be expanded as "main in, sub out"}} {{NoteTag|The {{slink||Alternative terminology}} section gives more details on proposed alternative terminology. See [[Talk:Serial Peripheral Interface#Terminology|the talk page]] for an ongoing discussion.}} where one{{NoteTag|For any given transaction, only one device is the main. However, some devices support changing main and sub roles on the fly. Most microcontrollers can easily reconfigure their SPI's role, and some Atmel and Silabs devices can change roles depending on an external pin.}} main device [[Signaling (telecommunications)|orchestrates communication]] with someone numberor ofmore peripheralsub (subperipheral) devices by driving the [[clock signal|clock]] and [[chip select]] signal(s)signals.

[[Motorola]]'s original specification (early 1980s) uses four [[Wire|wires]] to perform [[full duplex]] communication. It is sometimes called a ''four-wire'' [[serial bus]] to contrast with [[Serial Peripheral Interface#Three-wire|three-wire]] variants which are [[half duplex]], and with the ''two-wire'' [[I²C]] and [[1-Wire]] serial buses.

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Typical [[#Applications|applications]] include interfacing [[microcontrollers]] with peripheral chips for [[Secure Digital]] cards, [[liquid crystal display]]s, [[analog-to-digital]] and [[digital-to-analog converters]], [[Flash memory#Serial flash|flash]] and [[EEPROM#Serial bus devices|EEPROM]] memory, and various communication chips.

Although SPI is a synchronous serial interface,<ref>{{cite web |url= https://digital.ni.com/public.nsf/allkb/862567530005F09C862566BE004E469D |title= What is Serial Synchronous Interface (SSI)? |access-date= 2015-01-28 }}</ref> it is different from [[Synchronous Serial Interface]] (SSI). Both are a four-wire synchronous serial communication protocols, but SSI employs [[differential signaling]] and provides only a single [[simplex communication]] channel.

==Operation==