6-26 Intel® PXA26x Processor Family Developer’s Manual
Memory Controller
Power-Down (PWRDN)
Enter Self-Refresh (SLFRSH)
Exit Power-Down (PWRDNX)
No Operation (NOP)
Table 6 -12 shows the SDRAM interface commands. The table assumes the bank bits for the
SDRAM are sent out on external address lines MA<24:23>.
The programmable opcode for address bits MA<24:17> used during the mode-register set
command (MRS) is exactly what is programmed in the MDMRS register.
Table 6-12. SDRAM Command Encoding
Command
Pins
SDCKE
(at clk
n-1)
SDCKE
(at clk
n)
nSDCS
3:0 nSDRAS nSDCAS nWE DQM
3:0
MA <24:10>
24:23 22:21 20 19:10
PWRDN 101 1 111 x
PWRDNX 011 1 111 x
SLFRSH 100 0 010 x
CBR 1100 01x x
MRS 1 x 0 0 0 0 0 OP code
ACT 1x00 11xbank row
READ 1 x 0 1 0 1 0 bank col 0 col
WRITE 1 x 0 1 0 0 mask bank col 0 col
PALL
PRE
All 1x00 10x
xx1x
Bank bank 0
NOP 1x1xxx
xx
0111
Table 6-13. SDRAM Mode Register Opcode Table
Address Bits Option Value
MA<24:17> Reserved MDMRSx
MA[16:14] CAS Latency = 2 010
CAS Latency = 3 011
MA[13] Sequential Burst 0
MA[12:10] Burst Length = 4 010