difference between quad SPI and QPI

[balamanikandan]

hi


What is the difference between Quad Serial Peripheral Interface (SPI) and Quad Peripheral Interface (QPI) ?

 

[abhisayan]

I am pretty sure there is no such thing as QPI. There is of course an SPI and then there is a Quad SPI and there is also a queued SPI.
The 4b version of SPI is fundamentally Quad SPI but additionally also supports memory mapped access from a CPU.
Queued SPI offers more performance than a quad SPI for memory mapped access as it supports some buffering of transactions.