nRF5340 + 7002EK: rpu_validate_comms() check fails for SPI frequency of 16 MHz

[Ladivin]

Hello DevZone,

I have an nRF5340 devkit along with an nRF7002EK, and I'm looking to upgrade from SDK version 2.6.1 to 2.6.4. However, I'm facing an issue. In version 2.6.2, a new check was introduced in nrf\drivers\wifi\nrf700x\src\qspi\src\rpu_hw_if.c, specifically the rpu_validate_comms() function added to rpu_enable(). This check fails for me when I use an SPI frequency other than 8 MHz for communication with the nRF7002-EK.

To change the frequency I use the following property of nrf700x node in my device tree overlay: spi-max-frequency = <DT_FREQ_M(16)>

Is this intended behavior, or could it be a bug?

Also, I'm attaching a screenshot of the above mentioned failure:

Many thanks!

Ladivin

[Håkon Alseth]

Hi,

 

I see this issue on v2.6.x and v2.7.0, but it seems to be fixed on v2.8.0 and newer.

Do you see similar behavior as me?

 

Kind regards,

Håkon

[Ladivin]

Hi Håkon!

Thanks for your response. Actually, I can see this issue on 2.6.2, 2.6.3 and 2.6.4, but 2.7.0 works fine for me, because if I look into its nrf\drivers\wifi\nrf700x\src\qspi\src\rpu_hw_if.c the check that is failing is not present there. 

This leads me to a question - why are some of the Wi-Fi fixes backported to 2.6.X and not to 2.7.X? Is 2.6.X some kind of a long term support version? 

So far, I was not able to try out 2.8.0 or above, because our code is quite complex and I haven't succeeded in building it for 2.8.0. 

If I understand correctly, in general it is fine to have a nRF7002 on SPI (SPI4 in our case) with frequency of 16 MHz and there is no requirement to keep it on 8 MHz, correct? 

BTW what happens if I connect two devices with different frequency to the same SPI? Will the frequency change depending on which device I'm talking to, or will the lower frequency of these two be used? 

Thanks!

Ladivin