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154 SA-1110 Developer’s Manual
Memory and PC-Card Control Module
10.5.4 SDRAM Commands
The SA-1110 accesses SDRAM by using the following subset of standard interface commands:
• Mode Register Set (MRS)
• Bank Activate (ACT)
• Read (READ)
• Read with Auto-Precharge (READAP)
• Write (WRIT)
• Write with Auto-Precharge (WRITEAP)
• Precharge All Banks (PALL)
• Auto-Refresh (CBR)
• Power-Down (PWRDN)
• Enter Self-Refresh (SLFRSH)
• Exit Power-Down (PWRDNX)
• No Operation (NOP)
Table 10-9 shows the SDRAM interface commands.
Table 10-9. SDRAM Command Encoding
Command
SA-1110 Pins
SDCKE
(at clock n-1)
SDCKE
(at clock n)
nRAS/
nSDCS[3:0]
SDRAS SDCAS nWE
nCAS/
DQM[3:0]
DRA14-11,
DRA9-0
DRA10
PWRDN 1 0 1 1 1 1 4’b1111 x x
SLFRSH 1 0 0 0 0 1 4’b0000 x x
PWRDNX 0 1 1 1 1 1 4’b1111 x x
CBR 1 1 0 0 0 1 4’b0000 x x
MRS 1 x 0 0 0 0 4’b1111
Mode
(DRA[14:7] = 8’b0
DRA[6:4] = {1’b0, TDL},
DRA 3 = 1’b0,
DRA[2:0] = 3’b000)
ACT 1 x 0 0 1 1 4’b1111 Bank, row
READ 1 x 0 1 0 1 x Bank, column 0
READAP 1 x 0 1 0 1 x Bank, column 1
WRIT 1 x 0 1 0 0 Mask Bank, column 0
WRITEAP 1 x 0 1 0 0 Mask Bank, column 1
PALL 1 x 0 0 1 0 4’b0000 x 1
NOP 1 x 1 x x x x x x
NOP 1 x 0 1 1 1 x x x