While I’m waiting until my Mesh pre-order arrives I was digging a little deeper into the possibilities of these new devices.
I want to use 3rd party SIMs in these devices and just assumed that this would be an easy setup. But when having a look at the new hardware schematics it looks like this will be more difficult then first thought.
If you want to use a 3rd party SIM one needs to select channel 1 to work with the nano SIM card slot. Now instead of this being just a software selection using an IO pin for setting SIM slot selection it seems it’s done by hardware pullup or pulldown resistor.
So if I understand this correctly we need to re-solder this resistor to make use of 3rd party SIMs?
Problem is this resistor has a 0201 package, this is insane small to solder by hand
SIM_SELECT is a net connected to a u-blox GPIO, so you can control the SIM in software.
There is a pull-up, but you can override it in software. By populating the other resistor you could make the default the other way.
I did not look further because I saw that V_INT is also powering the SIM switch IC.
Is this not a problem then? If you set V_INT low then the FSA2567MPXMLP chip doesn’t receive power on VCC. If I look into the datasheet it states a minimum of 1.65V needs to be supplied to VCC.
Sorry, I gave the wrong answer in the post initially (I corrected it). It is still switchable, but because SIM_SELECT is a net. R14 is a pull-up, but that’s fine because the GPIO can drive SIM_SELECT low.
Ok indeed thank you, waw I missed that one