Hello @aliceyeh and welcome to the community;
First of all I apologize for my late reply.
The QUADSPI interface supports different memory types, you need to check the command format and order shared in the device datasheet must be aligned with the command format and order mentioned in the STM32 reference. There are volatile Quad-SPI SRAM (static random-access memory) available from Microchip, ON Semiconductor and others.
As mentioned in AN4760 section "3.3.3 Memory-mapped mode", in Memory-mapped mode the external memory is seen by the system as it was an internal memory. This mode allows all AHB masters to access the Quad-SPI memory as an internal memory. The CPU can execute code from the Quad-SPI memory as well.
For more information about the QUADSPI interface, I recommend you to look at:
- Quad-SPI interface on STM32 microcontrollers and microprocessors - Application note
- Overall FAQs for QUADSPI/OCTOSPI/HSPI/XSPI - STMicroelectronics Community
I hope this answer your request.
Thank you.
Kaouthar
