So I’m digging through how to make this work with the CM5 in a WisGate connect, and it looks like it uses the SDIO on the CM5…which is also used by the eMMC? So I have to disable onboard eMMC for this to work, or?
Just hunting to see what I can make work.
Hi @hammrind
My understanding of the compute module 5 datasheet is that the RPI1 peripheral chip provides interface alternative functions to the 40 pin expansion header. This header appears to be available on the Wisgate connect (is this the RAK7391?).
So unless I’m missing something, the CM5 onboard eMMC will be connected directly to the BCM2712, and the RP1 can be configured such that GPIO22-27 become expansion SDIO suitable for the HaLow hat.
This should be a very similar configuration to the RPi 5 package uploaded to this forum. Though the device tree files might need some tweaking.
Interesting - in my case the Alfa is an M.2 card and I’m using it in a PCI-E converter in Slot3 of the RAK.
Slot3 exposes the SDIO0 to the PCI-E card, so that should match the 40 pin header. I’m having a not great time finding a M.2 to mPCIE pinout to figure out what GPIO’s are going where - I’d say there is a 30% chance its gonna just work with the overlay as it is.
If I’m understanding it correctly, you’ve connected the Alfa M.2 card into an adapter for PCIe to SDIO? Please correct me if I’m wrong.
Which PCIe converter are you using? It sounds like you will need to add an SDIO bus entry in device tree for the additional converter as a child node to the relevant PCIe node, and then add another child node for HaLow underneath that new SDIO bus you added. ie, I don’t think this is mapping to the same SDIO0 as the 40p header!
In terms of GPIOs, it will probably depend on the converter.
Do you have any references to public schematics for the RAK board? Happy to help further where I can - especially with crafting some of the device tree entries.
So this is odd - the converter I’m using has no documentation. Its pretty much just a pin flipper that makes the m.2 NGFF card match up with teh mini-pcie-e pins. BUT I can’t seem to find any good description of what that would look like so that I can figure out what GPIO’s are matched up to some of the pins on the M.2.
As far as I can tell, the mPCIe slot that I’m using replicates the pins from the SDIO on the header. Its the RP1 SDIO 0 pins.
Documents on what I’m talking about are here - its in slot mPCIe-3
And I’m using this adapter:
I’m with you now. Cheers.
I’ll take a look and see if I can offer anything.
Hi @hammrind
So from the information available for the WisGate and compute modules. It looks like the compute module 5 has only 1 PCIe output. This is connected to a 1 - 4 PCIe expander on the WisGate Connect which provides PCIe to the expansion slots.
With the expansion slot in the way, even if you could remap the compute module 5 pcie to SDIO, I would advise against this as it is the root of the PCIe tree and will impact the other expansion slots. I can’t determine if such a remap of pins is possible.
I’m not seeing SDIO on slot 3, just PCIe, USB, I2C, and SIM.
Whether or not the pins these interfaces are routed too have an SDIO alternative function is, unfortunately, irrelevant. I’ve found a pinout from the manufacturer of your converter board here: http://ableconn.com/upload/MPEX-M2WL-00BM.2pinout.pdf
It looks like the SDIO lines aren’t broken out from the M.2 E connector to the PCIe pins. So that won’t work.
If you must use the mini PCIe slot, you may want to look at using something like Seeed Studio’s WIO-WM6180, in SPI mode, in mPCIe slot 2. This won’t be able to use Wi-Fi powersave features though, as pin 31 of the mPCIe slot 2 connector isn’t connected on the WisGate.
To use SDIO, it looks like you will need to use the 40p Raspberry Pi header if it is available.
Probably not the answer you were hoping for. Please let me know if I need to clarify anything further or can help in any other way!
VERY helpful answer. Side note- this is why I think that Morse Micro will eventually take this market space.
Similar experiences with Newracom were useless.
We will order the Seeed studio card and see how that comes out. It seems a good solution. This use case has almost no idle situations with the Halow network so not having great power management isn’t going to kill us.
Happy to help!
Out of interest, what will be connected to PCIe slot 1? Just noting that the pins on this connector for SPI are the same as those on slot 2 so if they need to be mapped to alternative functions there will be additional challenges.
Nothing. Don’t need them all populated on this device.
