Write Image to the onboard eMMC on Compute Module 3+ 8GB/16GB/32GB
If you use a Compute Module with onboard eMMC:
Connect eMMC to development computer
Setting up the Pi-Tron
To be able to write an image to the internal Raspberry Pi eMMC memory on the CM3+, a few preparation steps are needed.
- Connect the Pi-Tron to your computer using a Micro-USB to USB-A cable or adapter. If your computer does not have a USB-A port, please consider using an adapter to realize the connection. An example is shown in the image below.
- Prepare or connect the power cable to the Pi-Tron, not shown in the image below, but do not turn on the power yet.
- See the next topic, on how to install the "rpiboot" program, to be able to access the eMMC memory and write to it.
Writing to the eMMC
For Windows development computers
Download and run the Windows installer to install the drivers and boot tool for the Compute Module with eMMC.
Start 'RPIboot.exe' and power up the Pi-Tron.
After rpiboot completes, a new USB mass storage drive will appear in the Windows explorer.
Now you can follow the Quickstart to write the image to the eMMC just like you would do with an SD card. Before going back to Quickstart, also take some time to visit the Raspberry Pi documentation on flashing eMMC memory on the CM3+ to get a better overview, see next topic on this page.
Description on the Raspberry Pi website:
Pi-Tron with and without eMMC
The Pi-Tron can be obtained with two different types of Compute Module. One without eMMC memory, the "Lite" version, and the "eMMC" version. The notable difference between the Lite and the eMMC Compute Module is, that the "Lite" version can only boot and use the SD card and the "eMMC" version can only boot and use the eMMC memory, but not the SD card.
When using the Pi-Tron with eMMC memory, the SD card cannot be used, which means if additional storage is needed, it has to be added as USB storage, like a pen drive (USB stick) or an external USB HDD.
Overview SD card and eMMC combinations:
|Name||SD Card||eMMC Memory|
|AL Pi-Tron with CM3+ Lite||yes||no|
|AL Pi-Tron with CM3+ eMMC 8GB||no||yes|
|AL Pi-Tron with CM3+ eMMC 16GB||no||yes|
|AL Pi-Tron with CM3+ eMMC 32GB||no||yes|
|BL Pi-Tron with CM3+ Lite||yes||no|
|BL Pi-Tron with CM3+ eMMC 8GB||no||yes|
|BL Pi-Tron with CM3+ eMMC 16GB||no||yes|
|BL Pi-Tron with CM3+ eMMC 32GB||no||yes|
BL = Board Line version, no housing, access to 40 pin header possible
AL = Automation Line version with housing, 40 pin header not accessible
Q: Why can the SD card not be used, when the Pi-Tron has a CM3+ with eMMC?
A: The eMMC chip on the CM3+ is connected to the same SDIO interface as the SD card is. This one SDIO interface can only be used by one storage medium at a time, which means one can only use the SD card on the CM3+ Lite or only use the eMMC memory on the CM3+ with eMMC, but not the SD card. Both devices exclude one another. This is by design of the Raspberry Pi Foundations Compute Module, this is not a limitation of the Pi-Tron base board.
Q: The config.txt lists a 2nd SD card, where is it and how can it be used?
A: This second SD card is not on the Pi-Tron, it is an option for those customers who integrate the Pi-Tron BL version into their own base board. On based boards like these a second SD card slot can be implemented and the Raspberry Pi overlays can be used to create a second SDIO interface via the 40 pin header of the Pi-Tron. The Raspberry Pi Device Tree offers an overlay on which GPIOs the SDIO interface can be realized, but only the default can be used, which means GPIOs 22 to 27. Only these GPIOs are directly available on the 40 pin header of the Pi-Tron.