balenaFin eMMC vs/and/or CM3 eMMC

I understand a CM3 Lite comes without eMMC. However, I was wondering what would happen if instead of the CM3 Lite I were to insert a regular CM3 with let’s say the same capacity as the balenaFin eMMC.

Which eMMC would be used

  • the fin’s
  • the CM3’s
  • both
  • none


From our Fin FAQ -

The balenaFin supports the Raspberry Pi Compute Module 3 and 3+ Lite​ (CM3L/CM3+L). “Lite” is important, it means that the module itself has no on-board storage and leaves the storage interface exposed in order to use the eMMC available on balenaFin.

Is there any particular reason that you want to use a non-Lite module?

I don’t want to :slight_smile: I am asking out of curiosity and because I want to get a better technical understanding of how the carrier board and the CM are integrated.

Hello @mar ,

If you connect a non-lite CM3, the eMMC onboard the fin will be effectively disconnected from the CM. This is because the SDx lines on the CM are electrically disconnected from the SoDIMM pins. You’ll only be able to use the eMMC onboard the CM.

Hope this helps.

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