How to increase attenuation value in Teseo III RF front-end?

[RSeny]

Hi!

UM2399 User manual ST Teseo III binary image on page 276 says:

"If a specific configuration is required (see RF front-end reference manual for details about registers) it can be achieved by setting in the proper way the configuration parameters in the range from 140 to 189."

https://www.st.com/content/ccc/resource/technical/document/user_manual/group1/26/c2/9b/50/db/3c/4f/e1/DM00495927/files/DM00495927.pdf/jcr:content/translations/en.DM00495927.pdf

I would like to find an information about RF front-end registers of the device (8089F) to increase RF front-end attenuation by 10 dB. We substitute 8088 by 8089 which has LNA and amplification is too hi for our input signal. I find it out by adding external attenuator - works fine CNO is 40-45. Without it works bad i think because of signal clipping.

Thank you in advance!

[Francesco Virlinzi]

Hi

We do not provide the complete RF front-end registers description but in this case:

Internal RN-LNA gain can be tuned setting some specific CDB-ID in the firmware configuration.

In your case you have to set:

CDB-140 @ 0x0A

CDB-141 @ 40

if it helps, you can also tests different vales for CDB-141 (140 is mandatory @ 0x0A)

Hope this helps

Regards

Francesco

[RSeny]

Hi, Francesco!

Thank you for the reply! I suppose to check it soon.

By the way I suspect that there is no range check for parameter number. And I think that with RF front end registers we have the same picture.

With different SW versions you have various parameters qty in parameters groups. I need to read version number and adjust pars qty to prevent range problem. Otherwise changing par in one group with command can cause changing parameters in other group. Or it can brick the module. I tried to write wrong front-end register and it also caused death (no uart communicaton at all). Is there the way to bring it back to life? I tried powercycle, reset and so on - no effect.

Thank you one more time!

Regards

Ruslan

[Francesco Virlinzi]

Hi

>  Is there the way to bring it back to life? I tried powercycle, reset and so on - no effect.

with the standard booting configuration (SQI mode) You can

1. perform a Firmware-update operation (using an UPG file) with:

• RECOVERY mode enabled
• ERASE NVM enabled

Or

2. reprogram the Teseo3-IC from zero (booting from UART and using a BOOT file)

Hope this helps

Regards

Francesco