Mapping SPI flash memory span to avalon bus.

[Altera_Forum]

Hi All, 

 I have a board using an SPI serial Flash hooked on the FPGA. I would like to map the whole span of this memory on the avalon bus for making it available to the Nios (some strings in that flash that I want to be able to address directly with pointers).  In other words, the goal is to abstract the serial interface.  How to achieve this? I have not seen any SOPC components that does this in the available memory interfaces.  From a bit of research it seems the EPCS chips are SPI-based. Would an EPCS controller do the job, or do I require to write my whole state machine + wrapper?  Thanks for any help.  Martin

[Altera_Forum]

Yes, the EPCS controller will give you access to SPI based flash devices. I do not know if it will support all flavors, but I know it works with the old ST/numonix/micron M25P series

[Altera_Forum]

It gives access to a SPI based flash memory, but doesn't provide a full memory map on an Avalon bus. It provides registers that you can use to send instructions and read the results, so you need a piece of software to read and write a specific part of the memory. This is provided in the driver. 

If you really want to map the flash contents into the Avalon memory space, then you'll have to write your own component.