Things You Should Know About the Serial Peripheral Interface (SPI)

Communication plays an important role in embedded system designing. SPI Communication of electronic devices is just like communication of humans, both sides require to speak the same language. These languages in electronics are called communication protocol. The embedded system generally uses SPI to communicate with the peripherals. SPi is the common hardware interface people use in microcontroller development. It is used to transfer data between integrated circuits by using a reduced number of data lines.

The three most common multi-wire serial data transmission formats that are in use for decades are UART, SPI, and I2C. This article looks at the serial peripheral interface which provides full-duplex synchronous communication between a slave and master device by using four data lines. It is a common communication protocol that is used by many master devices such as RFID card reader modules, SD card, and 2.4 GHz wireless receivers/transmitters all use SPI to communicate. You can transfer the data without interruption, which is one of the best benefits of SPI. It was developed in 1972 by Motorola.

It is available on most popular communication controllers such as AVR, PIC, and ARM controller, etc. it consists of 4 wires such as MOSI, MISO, SS, CLK used slave/master communication. It is designed for microcontrollers to connect. SPI operates at faster data transmission rates such as 8Mbits or more. It can be used in places where speed is important, such as display modules, SD cards, or when information changes and updates quickly.

It operates at a full-duplex where data can be received and sent simultaneously. It is two simple shift registers in the internal interfaces. It is used to communicate at high speeds over short distances. It is a synchronous communication protocol.

Pros and cons of SPI

There are some pros and cons of using the serial peripheral interface, and you should know when to use it according to the requirements of your projects:


  • It is a full-duplex communication protocol.
  • It is simple as there is no complicated slave addressing system.
  • Having high-speed data bus 10MHzs.
  • Separate MOSI and MISO lines which mean data can be received and transmitted at the same time.
  • While transferring, SPI is not limited to 8bits.


  • It uses 4 lines- MISO, NSS, MOSI, and NCLK.
  • The practical limit to no. of devices, more pin ports are occupied.
  • Allows for only one master
  • There is no form of error checking like in UART.
  • No acknowledgment mechanism that confirms whether data is received.
  • Also, there is no specified flow control.

Hence SPI has been between us for decades, there is no reason to expect it to go away. It is a straightforward and versatile serial communication interface that is amazing for certain master devices and slaves.

This is all about the serial peripheral interface, hopefully, this article has given your better details. We appreciate your attention and interest in this article and we accept your viewpoint on this article. Hence for any interfacing assistance and coding, feel free to ask us by commenting below.

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