RPI CM4 Adapter for DevTerm & CPI v3.14

Great news, everyone! You can now put Raspberry Pi CM4 into DevTerm, with just one adapter board, introducing RPI CM4 Adapter for DevTerm & CPI v3.14!
Now all you need is to find a Raspberry Pi CM4 computing module, at a reasonable price :sweat:


Having onboard eMMC storage is very interesting. This may help to gain a lot of performance.

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How does the CM4 compare with the A06? It looks like it’s hard to compare direclty. If I’m reading this right, the A06 has six processors (two faster Cortex-A72s and four slower Cortex-A53) to the CM4’s quad core. However, the CM4 can have a lot more memory.

And the eMMC looks linteresing, but I’m not sure how much faster it would be than the SDI. Also, I’ve already upgraded to a much larger SDI card–so if I wanted to keep using that, I’d need to get the “ilte” version without eMMC.

Did I miss anything?

So, performance wise, it looks like it comes down to whether more and faster cores will help you more, or would more memory help more. I suspect going up to 8 GB of ram might make the CM4 faster in most cases. But that’s really just a guess.

Would this just use Raspberry Pi OS, or would there be additional packages provided from Clockwork Pi repositories? Interested to see this!

Maybe this is a dumb question, but if you get a CM4 for your DevTerm, how exactly are you supposed to flash the emmc module? Can the dev term go into some USB boot mode to accommodate it? Or do you need some kind of break-out board to flash the CM4?

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Not a dumb question at all, this is a super interesting subject, hope that others are able to advise on this as I’m not sure!

Probably need another CM4 adapter board. Doesn’t look like this one has a USB socket on it like most of the others do. I use a little board from Waveshare to program the eMMC on the CM4’s then pop them off of that and onto whatever else.

We’d have to see the schematic of this board to see if ithey route any of that thru the edge connector to maybe the UART plug on the expansion module.

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Ah nice! Would you mind sharing with us the exact board you use and/or where the best place would be to pick one up? Or if there are cheaper/easier solutions that exist, which one you would personally recommend?

Waveshare makes a ton of toys, but this one is super useful and cheap. https://www.amazon.com/gp/product/B09VX96DV6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

YOu can also buy direct from Waveshare, but in the US Amazon has them stocked and delivered quickly.

Basically the little switch on the side controls what the USB-C port is doing. If it’s a power port or acting as a device port. Flip one way and you power the module for use, flip the other and you plug into a computer to program the eMMC.

Slightly off topic: Is emmc significantly faster than SD card performance? Or is getting a high end SD card just as good as emmc for cm4 use? The reason I found the cm4 module appealing, was because I was hoping the emmc would reduce the slow SD load times of the A06.

I’ve found eMMC to be quite a bit faster then SD cards in a RasPI. Probably due more to the nature of how the SD cards are connected to the bus. They also tend to be quite a bit more reliable.

The annoying bit with Clockwork is losing access to the SD card when using a CM4 with eMMC. Most CM4 carrier boards don’t do that. You still get to access the SD card as yet another storage device.

I think 32GB EMMC is not enough compared to 128GB or bigger SD cards.

still CM4 is too expensive at this time.

So, should I buy a CM4 with or without EMCC (prices are different).

Hooray! :partying_face:

Can you please add to wiki or here how to build cm4 image/kernel

Like in this sections

and patch for kernel mb

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I just installed the CM4 board, and it works brilliantly. The DevTerm is now the little Pi machine I’ve always wanted.

In addition to the Clockwork disk image, you’ll need a CM4 I/O board (or similar) and Raspberry Pi usbboot from Github to write the OS to emmc. Jeff Geerling made a super helpful video: https://youtu.be/jp_mF1RknU4


Can I just confirm that the OS must be written to eMMC? Is an SD card install not an option for the CM4 board?

Where is pin1? The CM4 fits EITHER way no key or pin1 indicated.

Refer to the pictures at the top of the thread? It shows the orientation of the CM4 to the adapter.

If your CM4 has eMMC you must use that, as the SD card won’t be available. If your CM4 doesn’t have eMMC, the Devterm SD card will work fine.