H7R3 External Memory Loader Issues - Macronix NOR Flash

[UCAC]

Hi!

I have a custom PCB with H7R3Z8T6 & MX25L12833F (16MB Marconix NOR-Flash) hooked up with XSPI1 (Quad SPI). I have been having a very difficult time programming the external memory with the External Loader in CubeIDE.

I have followed a forum post (https://community.st.com/t5/stm32-mcus/how-to-create-an-external-flash-loader-for-an-stm32h7rs/ta-p/742005) as a guide to getting started (also https://www.st.com/content/st_com/en/support/learning/stm32-education/stm32-moocs/external_QSPI_loader.html). The only real difference between the guide and my project is I am powering the memory with 3.3V and therefore did not enable HSLV option byte.

My issue is that when I flash the Appli firmware, it fails to verify: (Data mismatch found at address 0x90000002 (byte = 0x00 instead of 0x01). When I read the 0x9... register in CubeProgrammer, it is all zeros until ~0x9003XXXX, after which 0xFFFFFFFF is read (see screenshot below). The extact register where 0xFFFFFF03 is read varies, it changes every time I re-read the memory.

My inital impression was that as long as I had chosen 'Macronix' in the XSPI settings, and configured the clk + other parameters correctly, the auto generated CubeMX external loader & NOR-SFDP would take care of the rest.

Has anyone else experinced anything similar?

[KDJEM.1]

Hello @UCAC and welcome to the community;

What is the frequency of xspi?
Can you specify which curves you are observing on the oscilloscope?

I recommend you to refer to AN5050 precisely 7 OCTOSPI application examples and 8 XSPI application example configuration with STM32CubeMX sections.

Thank you.

Kaouthar