Editing Serial Peripheral Interface (section)

===Daisy chain configuration===
[[File:SPI_three_slaves_daisy_chained.svg|thumb|229x229px|Daisy-chained SPI]]
Some products that implement SPI may be connected in a [[Daisy chain (electrical engineering)|daisy chain]] configuration, where the first slave's output is connected to the second slave's input, and so on with subsequent slaves, until the final slave, whose output is connected back to the master's input. This effectively merges the individual communication shift registers of each slave to form a single larger combined [[shift register]] that shifts data through the chain. This configuration only requires a single {{Overline|SS}} line from the master, rather than a separate {{Overline|SS}} line for each slave.<ref>[https://www.maximintegrated.com/en/app-notes/index.mvp/id/3947 Maxim-IC application note 3947: "Daisy-Chaining SPI Devices"]</ref>

In addition to using SPI-specific slaves, daisy-chained SPI can include [[Discrete component|discrete]] shift registers for [[Shift register#More I/O pins|more pins]] of inputs (e.g. using the [[Shift register#Parallel-in serial-out (PISO)|parallel-in serial-out]] [[List of 7400-series integrated circuits|74]]<nowiki/>xx165)<ref name=":3">{{Cite web |last=Gammon |first=Nick |date=2013-03-23 |title=Gammon Forum : Electronics : Microprocessors : Using a 74HC165 input shift register |url=https://www.gammon.com.au/forum/?id=11979 |url-status=live |archive-url=https://web.archive.org/web/20230729042912/http://www.gammon.com.au/forum/?id=11979 |archive-date=2023-07-29 |access-date=2023-08-03 |website=Gammon Forum}}</ref> or outputs (e.g. using the [[Shift register#Serial-in parallel-out (SIPO)|serial-in parallel-out]] [[List of 7400-series integrated circuits|74]]<nowiki/>xx595)<ref name=":2">{{Cite web |last=Gammon |first=Nick |date=2012-01-31 |title=Gammon Forum : Electronics : Microprocessors : Using a 74HC595 output shift register as a port-expander |url=https://www.gammon.com.au/forum/?id=11518 |url-status=live |archive-url=https://web.archive.org/web/20230714101259/http://www.gammon.com.au/forum/?id=11518 |archive-date=2023-07-14 |access-date=2023-08-03 |website=Gammon Forum}}</ref> chained indefinitely. Other applications that can potentially interoperate with daisy-chained SPI include [[SGPIO]], [[JTAG]],<ref>{{citation |title= Interfaces |year = 1977|url= https://books.google.com/books?id=8od7phxJHGkC |pages= 80, 84}}</ref> and [[I2C|I<sup>2</sup>C]].