MOSI/MISO and 140 Years Of Wrong @make

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MOSI/MISO and 140 Years Of Wrong

The engineers who developed SPI in the late 1970s had to come up with a shorthand to indicate that one component controlled the data dialogue and gave the orders, while the other took the orders and only responded within a limited set of expected norms. Master/Slave was the engineering norm.

But these words are not appropriate and we at Make: will stop using those terms in our books, magazine, and online articles. Unfortunately, that can’t erase the millions of MOSI/MISO boards already in existence. What do we do about them?

Following what we think will become standard practice, from now on, our default for MOSI/MISO will be to call them “Main Out/Serial In” and “Main In/Serial Out”, a practice already being followed by Adafruit and others. When more information is available about a specific circuit, the initials can become more precise …

…the Open Source Hardware Association (OSHWA) has put forth a proposal to rename “master” and “slave” components to “controller” and “peripheral”. As we wait for COPI/CIPO boards to become the norm, we welcome these changes to nomenclature throughout the electronics industry.

Read more.


Featured image on MAKE by Artur Shamsutdinov from Pixabay.

Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here:

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