Et r on Tech
EM6A9320
4Mx32 DDR SDRAM
Figure 10. Self Refresh Timimg
CK
200xCK
tSREX
SREF
SRE
NOP
CMD
CMD
CKE
Self Refresh Entry Self Refresh Exit
After 200 x CK, Command can be active
Figure 11. Precharge Command
CK
tRAS
tRP
tRC
ACT
RA
PRE
ACT
RA
CMD
A0-11
BA0-1
BA
BA
BA
Figure 12. Power Up Sequence
CK
200uS
NOP
tRP
tMRD
200xCK
tRP
tRFC
NOP PREA
EMRS
MRS
PREA
Precharge All
ARE ARE
2 or more
MRS
CMD
Power Up Precharge All
wait 200uS
EMRS set
MRS set
with A8=L
MRS set
Auto Refresh
Reset DLL
with A8=H
Figure 13. Mode Register Set Timing
CK
1xCK
tRP
tMRD
PREA
Precharge All
MRS CMD
MRS set After 1 x CK, Command can be active
CMD
Figure 14. Power Down Mode
CK
PRE NOP NOP
NOP
CMD
CKE
CMD
tPDEX
Power Down Mode Entry
Power Down Mode Exit
Etron Confidential
15
Rev 0.3
July. 2002
ETRON [ ETRON TECHNOLOGY, INC. ]
