Visible to Intel only — GUID: hco1416492479437
Ixiasoft
Visible to Intel only — GUID: hco1416492479437
Ixiasoft
3.18.2. AFI Parameters
The parameters described in the following tables affect the width of AFI signal buses. Parameters prefixed by MEM_IF_ refer to the signal size at the interface between the PHY and memory device.
Parameter Name |
Description |
---|---|
AFI_RATE_RATIO |
The ratio between the AFI clock frequency and the memory clock frequency. For full-rate interfaces this value is 1, for half-rate interfaces the value is 2, and for quarter-rate interfaces the value is 4. |
DATA_RATE_RATIO |
The number of data bits transmitted per clock cycle. For single-date rate protocols this value is 1, and for double-data rate protocols this value is 2. |
ADDR_RATE_RATIO |
The number of address bits transmitted per clock cycle. For single-date rate address protocols this value is 1, and for double-data rate address protocols this value is 2. |
Parameter Name |
Description |
---|---|
MEM_IF_ADDR_WIDTH |
The width of the address bus on the memory device(s). For LPDDR3, the width of the CA bus, which encodes commands and addresses together. |
MEM_IF_BANKGROUP_WIDTH |
The width of the bank group bus on the interface to the memory device(s). Applicable to DDR4 only. |
MEM_IF_BANKADDR_WIDTH |
The width of the bank address bus on the interface to the memory device(s). Typically, the log 2 of the number of banks. Not applicable to DDR4. |
MEM_IF_CS_WIDTH |
The number of chip selects on the interface to the memory device(s). |
MEM_IF_CKE_WIDTH |
Number of CKE signals on the interface to the memory device(s). This usually equals to MEM_IF_CS_WIDTH except for certain DIMM configurations. |
MEM_IF_ODT_WIDTH |
Number of ODT signals on the interface to the memory device(s). This usually equals to MEM_IF_CS_WIDTH except for certain DIMM configurations. |
MEM_IF_WRITE_DQS_WIDTH |
The number of DQS (or write clock) signals on the write interface. For example, the number of DQS groups. |
MEM_IF_CLK_PAIR_COUNT |
The number of CK/CK# pairs. |
MEM_IF_DQ_WIDTH |
The number of DQ signals on the interface to the memory device(s). For single-ended interfaces such as QDR II, this value is the number of D or Q signals. |
MEM_IF_DM_WIDTH |
The number of data mask pins on the interface to the memory device(s). |
Parameter Name |
Derivation Equation |
---|---|
AFI_ADDR_WIDTH |
MEM_IF_ADDR_WIDTH * AFI_RATE_RATIO * ADDR_RATE_RATIO |
AFI_BANKGROUP_WIDTH |
MEM_IF_BANKGROUP_WIDTH * AFI_RATE_RATIO * ADDR_RATE_RATIO. Applicable to DDR4 only. |
AFI_BANKADDR_WIDTH |
MEM_IF_BANKADDR_WIDTH * AFI_RATE_RATIO * ADDR_RATE_RATIO |
AFI_CONTROL_WIDTH |
AFI_RATE_RATIO * ADDR_RATE_RATIO |
AFI_CS_WIDTH |
MEM_IF_CS_WIDTH * AFI_RATE_RATIO |
AFI_CKE_WIDTH |
MEM_IF_CKE_WIDTH * AFI_RATE_RATIO |
AFI_ODT_WIDTH |
MEM_IF_ODT_WIDTH * AFI_RATE_RATIO |
AFI_DM_WIDTH |
MEM_IF_DM_WIDTH * AFI_RATE_RATIO * DATA_RATE_RATIO |
AFI_DQ_WIDTH |
MEM_IF_DQ_WIDTH * AFI_RATE_RATIO * DATA_RATE_RATIO |
AFI_WRITE_DQS_WIDTH |
MEM_IF_WRITE_DQS_WIDTH * AFI_RATE_RATIO |
AFI_LAT_WIDTH |
6 |
AFI_RLAT_WIDTH |
AFI_LAT_WIDTH |
AFI_WLAT_WIDTH |
AFI_LAT_WIDTH * MEM_IF_WRITE_DQS_WIDTH |
AFI_CLK_PAIR_COUNT |
MEM_IF_CLK_PAIR_COUNT |
AFI_WRANK_WIDTH |
Number of ranks * MEM_IF_WRITE_DQS_WIDTH *AFI_RATE_RATIO |
AFI_RRANK_WIDTH |
Number of ranks * MEM_IF_READ_DQS_WIDTH *AFI_RATE_RATIO |