SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
This section describes the external connections of the two EMIF modules.
Figure 15-46 shows an example EMIF DDR2/DDR3 configuration without ECC memory connected.
Figure 15-47 shows an example EMIF DDR2/DDR3 configuration with ECC memory connected.
For simplification the DDR PHYs and DDR I/Os are not shown. Only the I/O signals and their corresponding EMIF pins are shown.
Table 15-66 describes the EMIF module associated I/O signals used for connection to DDR2 and DDR3 memory types.
EMIF Pin Name | Device DDR2 and DDR3 I/O Signal Names | I/O(1) | Description |
---|---|---|---|
EMIF1 Data PHYs | |||
D[31:0] | ddr1_d[31:0] | I/O | Data bus |
DQM[3:0] | ddr1_dqm[3:0] | O | Data mask |
DQS[3:0] | ddr1_dqs[3:0] | I/O | Data strobe |
DQSN[3:0] | ddr1_dqsn[3:0] | I/O | Data strobe invert |
ECC_D | ddr1_ecc_d[7:0] | I/O | Data bus used for ECC (EMIF1 Only) |
DQM_ECC | ddr1_dqm_ecc | O | Data mask used for ECC (EMIF1 Only) |
DQS_ECC | ddr1_dqs_ecc | I/O | Data strobe used for ECC (EMIF1 Only) |
DQSN_ECC | ddr1_dqsn_ecc | I/O | Data strobe invert used for ECC (EMIF1 Only) |
EMIF1 Command PHYs | |||
A[15:0] | ddr1_a[15:0] | O | Row/column address bus |
BA[2:0] | ddr1_ba[2:0] | O | Bank select |
CK | ddr1_ck | O | Differential clock |
NCK | ddr1_nck | O | Differential clock |
CSN[0] | ddr1_csn[0] | O | Active low rank select signal (chip select) |
CKE | ddr1_cke | O | Clock enable |
CASN | ddr1_casn | O | Command |
RASN | ddr1_rasn | O | Command |
WEN | ddr1_wen | O | Command |
RST | ddr1_rst | O | Active low asynchronous reset (DDR3 only) |
ODT[0] | ddr1_odt[0] | O | On-die termination enable signal |
EMIF2 Data PHYs | |||
D[31:0] | ddr2_d[31:0] | I/O | Data bus |
DQM[3:0] | ddr2_dqm[3:0] | O | Data mask |
DQS[3:0] | ddr2_dqs[3:0] | I/O | Data strobe |
DQSN[3:0] | ddr2_dqsn[3:0] | I/O | Data strobe invert |
EMIF2 Command PHYs | |||
A[15:0] | ddr2_a[15:0] | O | Row/column address bus |
BA[2:0] | ddr2_ba[2:0] | O | Bank select |
CK | ddr2_ck | O | Differential clock |
NCK | ddr2_nck | O | Differential clock |
CSN[0] | ddr2_csn[0] | O | Active low rank select signal (chip select) |
CKE | ddr2_cke | O | Clock enable |
CASN | ddr2_casn | O | Command |
RASN | ddr2_rasn | O | Command |
WEN | ddr2_wen | O | Command |
RST | ddr2_rst | O | Active low asynchronous reset (DDR3 only) |
ODT[0] | ddr2_odt[0] | O | On-die termination enable signal |
The CKE memory pad is dynamically driven by the EMIF module according to the memory interface activity. It can also be forced to tri-state by a dedicated Control Module register. For more information, see Section 15.3.4.17 Forcing CKE to tri-state.
The index numbers 1 and 2 which are part of the EMIF DDR2 and DDR3 associated signals listed in Table 15-66 EMIF Associated I/O signals, column "Device DDR2 and DDR3 I/O Signal Names" should not be confused with DDR1 and DDR2 types of memories. They are used to indicate whether the corresponding signal is associated with EMIF1 or with EMIF2 controller. For example, ddr1_csn[0] signal is the chip select associated with EMIF1 and ddr2_csn[0] is the chip select associated with EMIF2.
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.
Compared to the DDR memories on the data bus, the DDR ECC memory must:
For a full list of supported DDR device types, frequencies, and topologies, refer to the routing guidelines of the device data manual.