I was reading the mPCIe pinout of BPI-R2 and noticed this:
And according to the mPCIe 1.2, pin 48 should be +1.5v instead of +5v, and pin 46 should be output, instead of a +5v input.
I also noticed all +1.5v inputs are NC in the minicard slot (except for 48, which is connected to +5V).
Wondering why the circuit designed like this, and also want to know what is “ePA 5v solution use”.
This is the special circuit of MTK, the 5G part of MT7615. If you use the external PA chip (ePA), you need 5V, but we only use the internal PA (iPA) for the 7615 module, so we not need to use the 5V
I checked the board again and I found:
- Pin 42, Pin 46, Pin 48 are supplied via R156, which seems NC on the board, and got 0V.
- Pin 47 and pin 49 are connected via R158. Both of those pins are having +5V voltage.
And I found the Huawei’s define on their datasheet about Pin 47 and 49:
I think I have found out why my 4G module are broken after connected to this port. The R158 was ought to be removed from the board, isn’t it?
Damn! That sucks.
I think you’re right, @Silver_Bullet . @sinovoip should look into fixing this!
LTE modules generally do not have SIM card holders, but are placed on the motherboard, and R2 mpcie slots do not have USB
you can use this 4G module http://wiki.banana-pi.org/4G_module_via_USB