Skip to main content
dan0
Associate II
March 27, 2020
Solved

Can't deference memory mapped qspi

  • March 27, 2020
  • 3 replies
  • 1249 views

I am using memory mapped mode of the QSPI peripheral on an STM32L452. I can see in the memory view at address 0x90000000 the bytes i expect. However, when dereferencing the pointer to that memory all i get is 0xFF's.

In the attached photo you can see I expect to read xAA, xAA, xBB,xBB,xCC,xCC ... and so on. You can see those bytes in the memory view, but all that i get is xFF.

This topic has been closed for replies.
Best answer by dan0

Hello All-

Thanks for the replys, but I've solved the problem. I had the wrong number of dummy cycles programmed (0 when i needed 8). This was on a N25Q256 spi flash.

3 replies

alister
Senior III
March 30, 2020

Perhaps the Memory window's accesses are adversely affecting it, and if not the mapped memory, perhaps the memory below is paged and impacting something. Try repeating from boot without the memory window.

dan0
dan0Author
Associate II
March 30, 2020

I tried from boot w/out a memory view but still read 0xFF. Thanks for the idea though.

Tesla DeLorean
Guru
March 31, 2020

Seems like you need to revisit your QSPI support code.

What chip is being used here?​

Tips, Buy me a coffee, or three.. PayPal VenmoUp vote any posts that you find helpful, it shows what's working..
dan0
dan0AuthorBest answer
Associate II
March 31, 2020

Hello All-

Thanks for the replys, but I've solved the problem. I had the wrong number of dummy cycles programmed (0 when i needed 8). This was on a N25Q256 spi flash.