8.7.3.3 DDR3 Device Combinations
Because there are several possible combinations of device counts and single- or dual-side mounting, Table 8-43 summarizes the supported device configurations.
Table 8-43 Supported DDR3 Device Combinations(1)
| NUMBER OF DDR3 DEVICES |
DDR3 DATA DEVICE WIDTH (BITS) |
MIRRORED? |
DDR3 EMIF WIDTH (BITS) |
| 1 |
16 |
N |
16 |
| 2 |
8 |
Y(2) |
16 |
| 2 |
16 |
N |
32 |
| 2 |
16 |
Y(2) |
32 |
| 3 |
16 |
N(4) |
32 |
| 4 |
8 |
N |
32 |
| 4 |
8 |
Y(3) |
32 |
| 5 |
8 |
N(4) |
32 |
- This table is per EMIF.
- Two DDR3 devices are mirrored when one device is placed on the top of the board and the second device is placed on the bottom of the board.
- This is two mirrored pairs of DDR3 devices.
- The DDR memory connected to the DDR ECC bus does NOT need to be the same part number as the DDR memories connected to the DDR data bus. However, some constraints do apply. When selecting a memory for the DDR ECC bus, the following restrictions must be adhered to as compared to the DDR memories on the data bus:
- Match the same DDR3 speed grade
- Have an equal number of internal banks
- Have an equal number of columns
- Have a greater or equal number of rows