Alan Freedman -- The Computer Language Company - Computer Desktop Encyclopedia
Computer Desktop Encyclopedia
Longest-Running Tech Reference on the Planet

A CDE Definition

You'll love The Computer Desktop Encyclopedia (CDE) for Tech Term of the Day (TTOD)


SPI bus

(Serial Peripheral Interface bus) A four-line, synchronous, serial bus from Motorola that is widely used to connect a microcontroller to peripheral chips on a circuit board. Each device has one input line and one output line, and data are exchanged in full-duplex mode. SPI operates in a master-slave topology where the microcontroller is the master and clock controller, and the peripheral chips respond as slaves. SPI is typically faster than the I2C bus. See I2C bus.

SPI on a Microcontroller
This Ramtron microcontroller (MCU) includes controllers for both SPI and I2C buses for peripheral data transfer (note upper right of diagram). (Image courtesy of Ramtron International Corporation,

I2C bus

(Inter-IC bus) A two-line, synchronous, serial bus that is widely used to connect chips together on a circuit board. Also called the "I-squared-C bus" and developed by Philips in the 1980s, it is used as a control bus for every variety of chip from sensors to microprocessors. One chip, typically a microcontroller or DSP, functions as a master and initiates requests, and all other chips are slaves that respond to the master. See SPI bus and IPMI.

Personal Use Only

Before/After Your Search Term
spell checkSPI firewall
spell checkerSPI router
SPFXspidering program

Terms By Topic
Click any of the following categories for a list of fundamental terms.
Computer Words You Gotta KnowSystem design
Job categoriesUnix/Linux
Interesting stuffPersonal computers
InternetIndustrial Automation/Process Control
Communications & networkingAssociations/Standards organizations
HistoryDesktop publishing
ProgrammingHealthcare IT
System design