Sub GHz transceiver daughter board with SPIRIT1 - Schematic Clarification

[Silas Valera]

Posted on November 27, 2017 at 01:14

Hi 

I planning to use either SPIRIT1 or S2-LP for my project on WMBus. Refering to the schematic (

http://www.st.com/content/ccc/resource/technical/layouts_and_diagrams/schematic_pack/d0/6d/01/df/b4/8f/43/75/steval-ikr002v4b_schematic.pdf/files/steval-ikr002v4b_schematic.pdf/jcr:content/translations/en.steval-ikr002v4b_schematic.pdf

), there are these four resistors (R6-R7 in the lower left corner) which are soldered for the selected operation frequency. These are shown to be connected between GND to GND !!  Can anyone explain how do these resistors work and affect the frequency of operation? It may be that these are placed on the PCB exactly at the position needed so that the board will operate at the selected frequency. I am not sure and it is very confusing without any information.  Would anyone please explain?

Really appreciate your help!!

Thanks in advance!

Silas

#balun #spirit1-wmbus

[Tesla DeLorean · Accepted solution]

Posted on November 27, 2017 at 01:21

More indicative of a BOM difference and visual cue as to which board you are holding and what software is loaded.

[Silas Valera]

Posted on November 27, 2017 at 02:02

Thank you so much Clive One!

So sorry that logic did not hit me in first place

:(

 !! I could have seen the BOM.. 

Thanks again

Silas