Serial Peripheral Interface

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Typical SPI bus: master and three independent slaves

The Serial Peripheral Interface (SPI) is a synchronous serial communication interface specification. It is used for short-distance communication, primarily in embedded systems. SPI devices communicate in full duplex mode using a master-slave architecture.

The master (controller) device originates the frame for reading and writing. The SPI may be accurately described as a synchronous serial interface.[1] But it is different from the Synchronous Serial Interface (SSI) protocol.

Developer[change | change source]

The interface was developed by Motorola in the mid-1980s. Later it has become a de facto standard.

Pros and cons[change | change source]

Advantages[change | change source]

  • Full duplex communication in the default version of this protocol
  • Push-pull drivers (as opposed to open drain) provide good signal integrity and high speed
  • Higher throughput than I²C or SMBus. Not limited to any maximum clock speed, enabling potentially high speed
  • Complete protocol flexibility for the bits transferred
    • Not limited to 8-bit words
    • Arbitrary choice of message size, content, and purpose
  • Simple software implementation

Disadvantages[change | change source]

  • Requires more pins on IC packages than I²C, even in the three-wire variant
  • No in-band addressing; out-of-band chip select signals are required on shared buses
  • SPI does not support hot swapping (dynamically adding nodes)
  • Some variants like dual SPI, quad SPI, and three-wire serial buses defined below are half-duplex.

Applications[change | change source]

SPI Serial Memory by Atmel
  • Memory: SD Card , MMC , EEPROM , Flash.
  • Sensors: Temperature and Pressure.
  • Control Devices: ADC , DAC , digital POTS and Audio Codec.
  • Others: Camera Lens Mount, touchscreen, LCD, RTC, video game controller, etc.[2]

Sources[change | change source]

  1. "What is Serial Synchronous Interface (SSI)?". Retrieved 2015-01-28.
  2. Anusha (2017-06-20). "Basics of Serial Peripheral Interface (SPI)". Electronics Hub. Retrieved 2022-08-29.

Other websites[change | change source]