Editing Serial Peripheral Interface (section)

===Interrupts===
Interrupts are outside the scope of SPI; their usage is neither forbidden nor specified, and so may optionally be implemented.

==== From master to slave ====
Microcontrollers configured as slave devices may have hardware support for generating interrupt signals to themselves when data words are received or overflow occurs in a receive [[FIFO (computing and electronics)|FIFO]] buffer,<ref>{{Cite web |date=2002 |title=TMS320x281x Serial Peripheral Interface Reference Guide |url=https://www.ti.com/lit/pdf/spru059 |website=[[Texas Instruments]] |pages=16–17}}</ref> and may also set up an interrupt routine when their slave select input line is pulled low or high.

==== From slave to master ====
SPI slaves sometimes use an [[out-of-band signal]] (another wire) to send an interrupt signal to a master. Examples include pen-down interrupts from [[touchscreen]] sensors, thermal limit alerts from [[List of temperature sensors|temperature sensors]], alarms issued by [[real-time clock]] chips, [[Secure Digital#SDIO|SDIO]]{{NoteTag|Not to be confused with the SDIO (Serial Data I/O) line of the half-duplex implementation of SPI sometimes also called "3-wire" SPI. Here e.g. MOSI (via a resistor) and MISO (no resistor) of a master is connected to the SDIO line of a slave.|name=3wireSDI}} and [[audio jack]] insertions for an [[audio codec]]. Interrupts to master may also be faked by using [[Polling (computer science)|polling]] (similarly to [[USB 1.1]] and [[USB 2.0|2.0]]).