External Flash and QSPI Settings

[Fan Jiaming]

I have tried to study the behavior of the QSPI and the external flash. I noticed that the QSPI_CONFIG_READOC and QSPI_CONFIG_WRITEOC settings in sdk_config.h cannot be set to use a higher data lines.

More specifically, the QSPI_CONFIG_READOC can only be set to Read2IO and QSPI_CONFIG_WRITEOC to PP. Anything above would cause the FATFS module to throw an error and the USB MSC to not recognize the drive (For some reasons, PP2O works on USB MSC but not FATFS).

I have set QSPI_CONFIG_SCK_DELAY to 255 and QSPI_CONFIG_FREQUENCY to 32MHz/16, so it might not be a clock issue.

Anyone succesfully use more data lines?

[Hung Bui]

@Fan: We should go step by step. Have you tried \examples\peripheral\qspi , no modification ? As far as I can see it's using Read4IO for reading and PP4IO for writing. And it's working well on my computer.

There is a note in the \examples\peripheral\usbd_msc\ that says:

This example allows you to manipulate the file system (on QSPI memory) only while USB is not connected. If USB is connected, access to the file system from a user application is not possible because MSC is not designed to allow access to the file system from multiple sources.