Read data directly from external nor flash

RE: Read data directly from external nor flash

Amanda Hsieh — Tue, 04 Feb 2025 16:00:12 GMT

Hi,

Sorry for the misleading. The QSPI HAL only supports nRF5340. As I said previously, there is no support for XiP for the nRF52840 in the nRF Connect SDK.

RE: Read data directly from external nor flash

Eyal_Gal — Sun, 02 Feb 2025 18:32:22 GMT

checking the product spec on your site of nrf52840 + the nrf52840.h from the old sdk (mbk) + the NRF_QSPI_Type type taken from the nrf52840.h file in the nrf dir in nrf connect it seems there is no XIPEN register, only XIPOFFSET, am i to understand that it is always active ? if not i need an example on how to activate it in nrf52840 as even the product spec doesn't explains it. again i do not fear for race condition cause i read specific areas into ram and use them later on from there and next time is 24 hours later...

RE: Read data directly from external nor flash

Amanda Hsieh — Mon, 27 Jan 2025 20:24:22 GMT

While it is possible to set up the XIP window using registers directly with the QSPI HAL, you must be extremely cautious about the limitations imposed by Errata [216] QSPI: Race condition occurs in XIP.

RE: Read data directly from external nor flash

Eyal_Gal — Mon, 27 Jan 2025 15:29:13 GMT

Thanks for the reply Ammanda.

So the only option is to set the "XIP" window ourselves using the registers directly ?
our needs are very basic and i think are ok with the limiatation : read only code, we use the QSPI wire api to write the data and use XIP only to read the data "as if" it was from RAM.
I believe it's in the bounds of the ERRATAs.

which files (nrf\nrfx files) should we include' i don't belive any of them in the nrf-connect don't have ref to the registers, it's a bit strange that we'll have to write the the structs and pointers ourselves (though we can according to the product spec).

Or if it's not in the SDK, where was this code in nrf-sdk , maybe we can copy form there.

RE: Read data directly from external nor flash

Amanda Hsieh — Mon, 27 Jan 2025 15:24:38 GMT

Hi,

The nRF52840 has hardware support for XiP, but due to Errata 215 and 216, the support is severely limited for the nRF52840 w.r.t XiP. In nRF Connect SDK there is no support for XiP for the nRF52840.

-Amanda H.

RE: Read data directly from external nor flash

Eyal_Gal — Mon, 27 Jan 2025 14:42:21 GMT

Hi Amanda.

The post is irrelevant as it speaks of cache for XIP.
We are not talking about that, the request is simple:
An example of zephyr app (for nrf52840-dk) that uses XIP preferable the last 1 mb of the flash for reading (not executing anything of the external flash, just reading data). for now assume we don't care how the data got there, we don't need to flash it with nrfjprog and .hex file.

There are such examples for nrf53840 but not for nrf52840. For the very least a ref to the product spec and registers or driver you have (if you have) cause we were unable to find that data.

RE: Read data directly from external nor flash

Amanda Hsieh — Mon, 27 Jan 2025 13:57:01 GMT

Hi,

Check out this post.

Regards,
Amanda H.