This is from the E3800 Datasheet revision 3.6, section 12.1.1 ECC Support:
The system memory controller supports ECC. When ECC is enabled, only Memory
Channel 0 will be active. Memory Channel 1 will be disabled and used for the ECC data
signals. Signals on Memory Channel 1 not used for ECC will be tri-stated.
So ECC it is supported, the issue with the Board Planner should be reported.
Hello, Quinn and greggzeutzius! Thank you for bringing this to our attention. The Embedded Board Planner (EBP) has now been corrected to show that E3815 and E3825 do in fact support DDR3 with ECC. The E3815 and E3825 (entry and mid-level) processors support only one memory channel. Therefore, the error message on the EBP recommends that user to pick any of the other three SKUs (E3826, E3827, or E3845) to utilize two memory channels.
All E38xx series support 1 ECC channel for memory.
The E3805, E3815, and Ed3825 only support 1 channel of NON-ECC.
Then E3826, E3827, and E3846 also support 2 channels of NON-ECC memory.
Have a nice day!