Add miniPCIe interface to the board design?

[danielkucera]

Hello,

I am successfully using this firmware with LR1302 from Elecrow and my miniPCIe breakout board. This is my current setup.

Would you consider adding miniPCIe connector to your current HW design according to this spec? I tested the same setup also for RAK2287 and it works .

I was considering doing it myself but I don't have the design software to edit your project and I am lazy to design it from scratch.

[lora-gateway]

@danielkucera: Thanks for this proposal. Since the market already has some miniPCIe based modules available, it would be easier for people to have the hardware ready to play with.

First, I'd like to check if all of them (or most of them) follow the same spec; then I plan to create an interface board to bridge the miniPCIe connector to the motherboard. I need help from a friend to do this, so it would take some time.

BTW: What's your design software? Is it KiCAD? Maybe in the future, someone can help to convert the hardware design to such tool so more people can modify directly...

[danielkucera]

Thanks for the reply. Yes, I prefer KiCad. I even managed to import the board design and I am trying to add the interface. This is my current WiP:

Maybe I can manage on my own :)

[danielkucera]

First, I'd like to check if all of them (or most of them) follow the same spec;

I believe they all come from this reference design: https://www.semtech.com/products/wireless-rf/lora-core/sx1302cssxxxgw1#documentation

[dennis4lora]

Great, the design can support both kinds of interfaces, I think it's better than my idea to add a bridge board.

Still, I think there are compatibility issues needs to be noted.

First, I compared the miniPCIe Pins of RAK2287 and LR1302. Their SPI pins and a few other critical pins are the same; however, the pins for SX126x (used for LBT) doesn't match.

I believe they all come from this reference design: https://www.semtech.com/products/wireless-rf/lora-core/sx1302cssxxxgw1#documentation

I then checked the Semtech reference design, Oops! totally different from RAK2287 and LR1302, as below:

Which makes me doubt if Semtech has updated the design, while RAK2287 follows an earlier one?

So I checked a few such products selling in Chinese Market:

• product 1 follows RAK2287 design, doesn't support SX126x
• product 2 follows Semtech design
• product 3 follows RAK2287 design, but doesn't support SX126x

Conclusion: Compatibility issue does exist. If we don't need LBT (in fact ESXP1302 doesn't support it so far), then following the RAK2287 spec should support the major miniPCIe products available from market.

[danielkucera]

Oops! totally different from RAK2287 and LR1302

This completely slipped my attention, I was in the impression it is the same but you are right.

following the RAK2287 spec should support the major miniPCIe products available from market.

I totally agree.

[danielkucera]

So I had it manufactured.

The biggest surprise were those 0402 resistor pads - that is really something hard to assemble at home so I just bridged them with solder.

But anyway it works as expected 👌

[dennis4lora]

Great, congratulations! :+1:

[rwijbenga]

@danielkucera Could you share the schematic for the miniPCIe wirring to the ESP32 ?

Or the board files? :)

[danielkucera]

Hi @rwijbenga , I don't have Altium so I just imported the board to KiCAD and botched in minipcie and wired the connections. You can find it here: https://github.com/danielkucera/esxp1302/tree/minipcie/hardware_design/motherboard