SPI vs QSPI | Difference between SPI and QSPI

This page compares SPI vs QSPI and mentions difference between SPI and QSPI in tabular format. It provides difference between SPI and QSPI based on various factors such as interface diagram, data rate, distance, advantages, disadvanatages etc.


SPI interface diagram

• It operates in master slave configurations viz. 1 master and 1 slave, 1 master and multiple slaves.
• It uses clock which is generated by master and hence it is synchronous interface.
• It operates in half and full duplex modes.
• It has four lines MOSI (Master Out Slave IN) , MISO (Master IN Slave Out), SCLK (Serial Clock) , CS (Chip Select) or SS (Slave Select)
• Data rate: Usually supports about 10 Mbps to 20 Mbps
• Device addressing: Unlike I2C, it does not support device addressing.
• ACK support: It does not have mechanism to support receipt of the data unlike I2C interface.
• Advantages and disadvantages : Refer Pros and Cons of SPI Interface >> for more information.


QSPI interface diagram
Image Courtesy: STMicroelectronics

• QSPI is controller extension to SPI bus. It stands for Queued Serial Peripheral Interface.
• It uses data queue with pointers which allow data transfers without any CPU.
• In addition it has wrap-around mode which allows continuous transfer of data to/from queue without the need of CPU.
• In QSPI interface, peripheral acts as memory mapped parallel device for the CPU.
• Applications: To control ADC converter
• Other features of QSPI : chip select, transfer length delay
• QSPI is also abbreviation for Quad SPI as depicted in figure-2.

Following table mentions difference between SPI and QSPI.

Features SPI QSPI
Full Form Serial Peripheral Interface Queued Serial Peripheral Interface
CPU intervention Required Not require

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