SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
On coming out of reset, the EMIF controller begins the DDR3 initialization sequence after a write to any one of the following three registers, providing that the corresponding listed conditions are met.
For the first DDR3 initialization sequence, the EMIF controller performs the following actions:
Bits | Value | Description |
---|---|---|
A[15:11] | 0x0 | Reserved |
A[10:9] | EMIF_SDRAM_CONFIG[22:21] DYN_ODT | Dynamic ODT value |
A[8] | 0x0 | Reserved |
A[7] | EMIF_SDRAM_REFRESH_CONTROL[29] SRT | Self-refresh temperature range |
A[6] | EMIF_SDRAM_REFRESH_CONTROL[28] ASR | Auto self-refresh enable |
A[5] | 0x0 | Reserved |
A[4:3] | EMIF_SDRAM_CONFIG[17:16] CWL | CAS write latency |
A[2:0] | EMIF_SDRAM_REFRESH_CONTROL[26:24] PASR | Partial array self-refresh |
Bits | Value | Description |
---|---|---|
A[15:13] | 0x0 | Reserved |
A[12] | 0x0 | Output buffer enabled |
A[11] | 0x0 | TDQS disable |
A[10] | 0x0 | Reserved |
A[9], A[6], A[2] | EMIF_SDRAM_CONFIG[26:24] DDR_TERM | DDR3 termination resistor value |
A[8] | 0x0 | Reserved |
A[7] | 0x0 | Write leveling disabled |
A[5], A[1] | EMIF_SDRAM_CONFIG[19:18] SDRAM_DRIVE | SDRAM drive strength |
A[4:3] | 0x0 | Additive latency = 0 |
A[0] | EMIF_SDRAM_CONFIG[20] DDR_DISABLE_DLL = 0x0 | Enable SDRAM DLL |
Bits | Value | Description |
---|---|---|
A[15:13] | 0x0 | Reserved |
A[12] | 0x0 | Slow exit. The DDR3 SDRAM DLL is “OFF” after entering precharge power-down. |
A[11:9] | EMIF_SDRAM_TIMING_1[20:17] T_WR | Write recovery for autoprecharge |
A[8] | 0x1 | DLL reset |
A[7] | 0x0 | Normal mode |
A[6:4], A[2] | EMIF_SDRAM_CONFIG[13:10] CL | Value for CAS latency |
A[3] | 0x0 | Nibble sequential read burst type |
A[1:0] | 0x0 | Burst length of 8 |
The EMIF updates the DDR Mode registers if the DDR3 initialization sequence is triggered again. However, the EMIF controller first issues a precharge command and then starts from Step 3.
The EMIF does not perform any transactions until the DDR3 initialization sequence is complete.
When the EMIF comes out of reset, the delay time in Step 2 resulting from the 16 refresh rate intervals + 8 cycles is approximately 16 × REFRESH_RATE / input frequency.