3.3.17 UDDRC SDRAM Initialization Register 0

Name: UDDRC_INIT0
Offset: 0x0D0
Reset: 0x0002004E
Property: Read/Write

Bit 3130292827262524 
 SKIP_DRAM_INIT[1:0]    POST_CKE_X1024[9:8] 
Access R/WR/WR/WR/W 
Reset 0000 
Bit 2322212019181716 
 POST_CKE_X1024[7:0] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000010 
Bit 15141312111098 
     PRE_CKE_X1024[11:8] 
Access R/WR/WR/WR/W 
Reset 0000 
Bit 76543210 
 PRE_CKE_X1024[7:0] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 01001110 

Bits 31:30 – SKIP_DRAM_INIT[1:0]

If lower bit is enabled the SDRAM initialization routine is skipped. The upper bit decides what state the controller starts up in when reset is removed.

Programming mode: Quasi-dynamic Group 2

ValueDescription
00 SDRAM Initialization routine is run after power-up.
01 SDRAM Initialization routine is skipped after power-up. Controller starts up in Normal mode.
11 SDRAM Initialization routine is skipped after power-up. Controller starts up in Self-refresh mode.
10 Reserved

Bits 25:16 – POST_CKE_X1024[9:0]

Cycles to wait after driving CKE high to start the SDRAM initialization sequence.

DDR2 typically requires a 400 ns delay, requiring this value to be programmed to 2 at all clock speeds.

LPDDR2/LPDDR3 typically requires this to be programmed for a delay of 200 µs.

When the controller is operating in 1:2 frequency ratio mode, program this to JEDEC spec value divided by 2, and round it up to the next integer value.

Unit: Multiples of 1024 DFI clock cycles.

Programming mode: Static

Bits 11:0 – PRE_CKE_X1024[11:0]

Cycles to wait after reset before driving CKE high to start the SDRAM initialization sequence.

DDR2 specifications typically require this to be programmed for a delay of ≥200 µs.

LPDDR2/LPDDR3: tINIT1 of 100 ns (min)

When the controller is operating in 1:2 frequency ratio mode, program this to JEDEC spec value divided by 2, and round it up to the next integer value.

For DDR3 RDIMMs, this should include the time needed to satisfy tSTAB.

Unit: Multiples of 1024 DFI clock cycles.

Programming mode: Static