Is it 6678 DDR interface same as one of 66AK2H14 DDR interface?

Hello Xining,

66AK2H14 claims that it has two 72-Bit DDR3 Interfaces with Speeds Up To 1600 MHz. 6678 says that it has one 64-Bit DDR3 Interface. However, I found that, actually, this 72 bit interface is the same as 64 bit interface. The 72 bit interface is 64 Bit Data bus + 8 Bit ECC. Although 6678 claims to have 64 bits, it has the same 64 Bit width Data Bus and 8 Bit width ECC. Is that correct?

Yes, both 66Ak2H14 and C6678 have same 64 Bit width Data Bus and 8 Bit width ECC. In 66AK2H14 document, it mention both data width & ECC and in C6678 document, it mention only data width.

Second question, why the ECC DDR is missing on the 6678EVM that we purchased from TI(picture showing below)?

The EVM has the full 512MB of DDR3 on board.  That U6 pad would be used for the support of ECC memory bank.  It was designed so that testing could be done for ECC, but the production build doesn't include the memory bank for ECC support.

Regards,
Senthil