Problems using nRF7002 with non-nRF MCU

[djgj]

Hello All,
I am trying nRF7002 shield on my non-nRF MCU and i am running the wifi sample app on zephyr (latest version as of today Aug 20)
I get this error most of the time when issuing "wifi" shell commands. however commands are successful 50% of the time.
Has anyone seen this before? should i enable or disable any kconfig for this?

Regards,

djgj

[runsiv]

Hi Djgj

Could you give a bit more information regarding your system? As we can't test for all devices, the test level will be lower on non Nordic hosts. Due to this, there might be compatibility issues with helper libraries, such as the download library.

Regards

Runar

[djgj]

Hi Runar,

We are using RT500 MCU (NXP) as our host MCU. I connected our host MCU with nRF7002 EK via SPI connection. 

I am running the basic WiFi shell application on zephyr:

https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/net/wifi

All other configs are same as used with nRF5340 except the SPI interface part.

While debugging i also noticed this comment which can be related to my issue.
https://github.com/nrfconnect/sdk-nrfxlib/blame/main/nrf_wifi/hw_if/hal/src/hal_interrupt.c#L437

Do you know what this is about and how to mitigate this?

kindly let me know if you need more details.

Regards,

djgj

[djgj]

Thank you Marte, 

I also noticed that when i leave the setup for more than 5 minutes and try wifi scan command again. then nrf7002 kind of goes to off/low power mode and it does not wake up.

Is this also known issue? should i disable/enable something?

Regards,

djgj

[Marte Myrvold]

Hi,

Can you try disabling low power mode to debug the issue? You can do this by setting CONFIG_NRF_WIFI_LOW_POWER in prj.conf or adding it as a flag when building (-- -DCONFIG_NRF_WIFI_LOW_POWER=n).

Best regards,
Marte

[djgj]

Hi Marte, 

Issue about wake up is better when i disable CONFIG_NRF_WIFI_LOW_POWER. However i still see those invalid memory addresses most often along with other issues like timeouts. Overall the connection/interface is not stable enough to do any networking task. 

I tried to debug by connecting logic analyzer to SPI lines. However i do not know what each bytes represent to check anything meaningful.

Are these memory addresses transferred via SPI line to host? i could not see them in my logs?
Could you help me debug this issue and to what to look for in those analyzer logs?

How to prove it is an issue on either host MCU side or nRF7002? on the host side we have also verified that SPI lines are working and stable. Only in combination with nRF7002 we face this issue.

Regards,

djgj

[Marte Myrvold]

Hi,

I have forwarded this internally and will get back to you early next week.

Best regards,
Marte

[Marte Myrvold]

Hi,

The team has suggested some things you can do to debug the issue.

1. Measure the SPI clock while running the SPI at 2MHz or 1MHz to validate the frequency.
2. Measure the BUCKEN, IOVDD, and VBAT supplied to the nRF70.
3. Probe IOVDD and BUCKEN with an oscilloscope during boot to check the power sequencing.

The power-up sequencing requirements are as follows:

• Supply VBAT/BUCKVBAT/BUCKVBATS/AFEVBAT
• Wait ≥ 6 ms
• Assert BUCKEN
• Wait ≥ 1 ms
• Supply IOVDD

You can read more about this in supply sequencing requirements.

Please share the results of these tests.

It would also be helpful if you could share the hardware schematics of your host interface.

Best regards,
Marte

[djgj]

Hello Marte, 
              I have attached the salea logic analyser logs in this reply.
I have compared the init sequence of nRF7002 with nRF53 and RT595 devkits.

nRF7002 with RT595 EVK

nRF7002 with nRF5340 DK

* I do see some difference in the way init sequence is happening on RT500 compared to nRF53.
Do you think this can cause issue within that power cycle with nRF7002?

* Also once nRF7002 goes into error state what is the recommended to bring it back to proper state?
I noticed that once i use nRF7002 with nRF53 devkit and then switch to RT500 normally i don't see invalid addresses for sometime. But once the nRF7002 starts giving invalid address errors (for some reason like improper connections or init sequences) it continues on. I think there can be a link somewhere here.

I will verify the SPI frequency and voltage values on BUCKEN, IOVDD, and VBAT and confirm on it soon.

Additional Info/Question:

* I also added some log messages in the spi_if.c file to compare and see for any SPI errors between nRF53 and RT500.
https://github.com/zephyrproject-rtos/zephyr/blob/main/drivers/wifi/nrfwifi/src/qspi/src/spi_if.c#L29-L77

But however i don't see any of the bytes probed on nRF7002 SPI lines (via logic analyser) with those printed on spi_if driver logs

The data compared here is from nRF7002 driver itself which does some checking/sending a message every 10 seconds after just initialization (no other wifi commands issued and I did not add anything code for this here except those log messages on spim_xfer_rx/tx functions)

Technically it is just writing and reading to same nRF7002 registers every 10 seconds. But the bytes seen in SPI lines are different every time. This behavior is seen on both RT500 and nRF5340 setup too.  I would like know how to debug these message bytes so that i can know what kind of SPI error could be happening?

Regarding Host setup:

We are using NXP MIMXRT595-EVK as our Host MCU board and nRF7002 EK.
We are using devkits to verify this Wi-Fi interfacing path with nRF7002EK.

I was not able to use the full Arduino shield interface on RT595 EVK board since
their "arduino_spi" interface was not available out of the box for using on RT500

Instead, I connected nRF7002 EK pins partially to "Arduino" and "HS_SPI_1" pins on the RT595 EVK board.
(reference chapter 9 https://www.farnell.com/datasheets/3209290.pdf)

NRF7002 EK	RT5959 EVK
V5V	J29 - pin 5
GND	J29 - pin 6
VIO	J29 - pin 4
HOST_IRQ	J27 - pin 8
BUCK_EN	J27 - pin 2
IOVDD_EN	J27 - pin 1
SS	HS_SPI_1 - JP26 - pin 1
MOSI	HS_SPI_1 - JP26 - pin 2
MISO	HS_SPI_1 - JP26 - pin 3
CLK	HS_SPI_1 - JP26 - pin 4

And on the software side we are using latest zephyr containing Nordic updates on nRF7002.
App: https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/net/wifi

I made a small change on nrf7002ek.overlay to be able to use setup without too much custom changes.

Thanks,

djgj 

[Marte Myrvold]

Hi,

Thank you for providing additional debug information. I forwarded it internally and am waiting for a reply. If I have not heard anything by tomorrow, I will ask them for an update and get back to you.

Best regards,
Marte

[Marte Myrvold]

Hi,

I have not received a response yet but have asked for an update. I expect to hear something early next week.

Best regards,
Marte

[Marte Myrvold]

Hi,

djgj said:

I will verify the SPI frequency and voltage values on BUCKEN, IOVDD, and VBAT and confirm on it soon.

Do you have any updates on this?

What is the clock frequency of the host (RT595) that you are using? It seems to be pretty high. Can you clock it to 128 MHz, the same as the nRF5340, and collect the same logs as previously?

Best regards,
Marte

[Marte Myrvold]

Hi,

Are you still experiencing the issues in this ticket? If so, do you have an update on the questions in my previous reply?

Best regards,
Marte