WL1837MOD: EMI problem at 4.8GHz

Hi Massimiliano,

Has the customer run ./configure-devices.sh script to generate a wl18xx-conf.bin file that is correct for a WL1837MOD device. ( This is  "wlconf manual" listed as an app note on wl1837mod product page.

If the firmware knows it is a WL1837MOD is makes an adjustment to account for the 5GHz diversity switch in the WL1837MOD. This reduces the spur at 4.8GHz  enough to pass certification.

Iain

Hi Ian,

thanks a lot for your support.

I sent this information to the customer. I will let you know the feedback from the customer.

Thanks again.

Best regards,
Massimiliano.

Hi Ian,

Thanks for your reply.
Massimiliano passed me the link to the E2E, so I can also directly post follow-up questinons here.

We did indeed just use the standard wl18xx-conf-default.bin, and did not run the configure script to create one.

For our new certification round, I was looking into generating an appropriate .bin file. I can build the wlconf tool (git://git.ti.com/wilink8-wlan/18xx-ti-utils.git), and generate .bin files from the INI files.
There is a catch though. Due to reasons beyond our control, we are currently stuck at a 4.1 kernel, and are using the mainline TI kernel modules. (Which correspond at R8.5).

This has the following consequences:

- To make the kernel module “understand” the .bin file, I thus have to use a wlconf tool built from the R8.5 tag, since the header format/size was changed between then.
- The WL1837 ini files however are not yet in the R8.5 tag. Only the WL1835 ini files
- From what I can see from diffing R8.5 and R8.7 in the wlconf tool however, not much has changed. A few fields (num_short_intervals and long_interval) have been added
- I can just generate a 8.5-compatible .bin file with a R8.5 wlconf by using the the ini files I find in the 8.7 repository.

The biggest question I have now, is whether there is a real need in -firmware- upgrade from R8.5 to R8.7 or something for certification of the WL1837, or whether just using the -settings- from the R8.7 (as I describe above) is enough.

I quickly went over the release notes of the R8.6 (processors.wiki.ti.com/.../R8.6) ,and this states:

"
5G antenna diversity support (for supported HW - wl1837)
New 5GHz firmware-based diversity algorithm is introducing smart selection of the antenna to be used. (Supported only on WL1837 device)
"

I do not know if this has any important effect for certification (the 4.8Ghz spur), so hence also my question.

In case there is an important change in firmware beyond R8.5 that we would need for certification, and since backporting the R8.7 linux driver onto our v4.1 kernel is a non trivial effort, the question then becomes if we cannot just use the R8.7 -firmware- (wl18xx-fw-4.bin), whilst still using R8.5 kernel drivers.
(This does work, and does not suffer from some incompatibility issue at module loading, like the wl18xx-conf.bin does, but I'd like to get your opinion on this as well. If it is not needed in the first place, I'd rather just use kernel drivers + firmware from R8.5 together, unless this is a recommended procedure).


Long story short: Can you confirm that by using the correct wl18xx-conf.bin the WL1837 can be certified on R8.5 kernel drivers + firmware?

Thanks for your reply

Hi Arnouts,

From the feedback I got:

For latest certification (especially ETSI RED) you have to use our latest release (R8.7_SP2).
Note that the R8.7_SP2 firmware may not load correctly with R8.5 drivers (in any case this combination is not being tested).

We strongly advise to use R8.7SP2 and use the build script provided to re-build the SW for kernel 4.1 using backport.
Some instructions to get started can be found in section 4 of the below page:
http://processors.wiki.ti.com/index.php/WiLink_FAQ#Wi-Fi.C2.AE
Also an example that makes use of the backport (with KERNEL_VARIANT=4.1) is provided here:
http://processors.wiki.ti.com/index.php/WL18xx_First_Time_Getting_Started_Guide_(SAMA5D2-Xplained)

A.

Thank you Anber for your reply.

Somewhat off topic, but the TI git server does seem to be down at this moment. Any idea how to get it back up? Or is there a clone of git.ti.com/.../18xx-ti-utils somewhere?

Kind regards,
Arnout

Hi Arnout,

As spoken I have submitted at ticket to the IT team. I will try to check if we have a clone or mirror available.

A.

Hi,

Thanks, the server is back online.

Note though that R8.7_SP2 Vs R8.7_SP1 for example, only differences were made in the WL1835MOD* ini files, and NOT in the WL1837.
So as far as I can see, either the R8.7_SP1 was fine for ETSI RED, or files are still missing for WL1837?

Kind regards.
Arnout

Hi,

I know..

But the latest question was in regard with the ETSI RED changes (which I understood were from 8.7_SP1 -> 8.7_SP2) and the ini files.:

git diff R8.7_SP2..R8.7_SP1 --name-only
wlconf/official_inis/WL1835MOD_INI.ini
wlconf/official_inis/WL1835MOD_INI_C2PC.ini

=> There is no change in firmware, driver, .. between these versions, only config files. And only in the WL1835, not in the WL1837 files.

Hence my question whether this was forgotten, still missing, ..

Kind regards,

Arnout

Hi Arnout,

I hope that Saurabh will be able to clarify.

I found the below wiki entry about RED ETSI. It seems to document the SP and ini file to use. See at the end of the page for WL18xx:
http://processors.wiki.ti.com/index.php/Radio_Equipment_Directive_Updates

Regards,

A.