How to set resistors to control MUX?


#1

Hi all,

I want to configure the sim slot #2 to be connected to secondary CF3. According to the developer’s guide this can be done by setting the resistor of MUX1 to HIGH. How this can be done? I did not find any command that does this. Can somebody help me?

Best


#2

Please see document mangOH_Green_DV4_Fabrication, BOM_mangOH_Green_DV4 for more details of components name and placements.
Please unsolder the resistor R833 and solder it to place of resistor R820, see Pic 2.1, 2.2 for more details.
Resistor nominal and size are: RES, 10K, 5%, 1/16W, 50V, -55 +155C, 0402.


#3

Thank you so much for your thorough answer. It seems the hardware way of configuring the MUX is rather hard to achieve. I’d rather configure it by API command now.

But what confuses me is that in the DV4, there are only two pins on CF3’s GPIO expander are meant to control the MUX for sim, which are U906 I/O_6 and 7. I noticed I/O_7 is to control MUX2, so does that mean I can only control MUX3 via I/O_6?