MEMORY CONTROLLER
S3C2500B
5-44
5.7.4 SDRAM COMMANDS
The SDRAM controller issues specific commands to the SDRAM devices by encoding the nSDCS, nSDRAS,
nSDCAS and nSDWE outputs. Table 5-23. Lists all of the SDRAM commands understood by SDRAM devices.
The controller supports a subset of these commands.
Table 5-23. SDRAM Commands
Command
CKE
nSDCS
nSDRAS nSDCAS
nSDWE
BA
A10/AP Mnemonic
Mode Register Set (MRS)
H
L
L
L
L
OP code
MRS
Refresh
Auto refresh
H
L
L
L
H
X
REF
Self refresh
L
L
L
L
H
SREF
Row activate
H
L
L
H
H
V
X
ACT
Read
with auto
precharge
H
L
H
L
H
V
H
RDA
without auto
precharge
L
RD
Write
with auto
precharge
H
L
H
L
L
V
H
WRA
without auto
precharge
L
WR
Burst stop
H
L
H
H
L
X
BST
Precharge Bank selection
H
L
L
H
L
V
L
PRE
All banks
X
H
PALL
Active power down
L
H
X
X
X
X
APWDN
Precharge power down
L
H
X
X
X
PPWDN
No operation
H
H
H
H
H
NOP
NOTE:
Shaded boxes indicate commands not supported by SDRAM controller. They are included for completeness.
X = Don't care
V = Valid value (H or L)
A10/AP = ADDR[10] /Auto Pre-charge
Summary of Contents for S3C2500B
Page 2: ...S3C2500B 32 BIT RISC MICROPROCESSOR USER S MANUAL Revision 1 ...
Page 17: ......
Page 25: ......
Page 80: ...PRODUCT OVERVIEW S3C2500B 1 46 NOTES ...
Page 296: ...MEMORY CONTROLLER S3C2500B 5 60 NOTES ...
Page 531: ...GDMA CONTROLLER S3C2500B 12 24 NOTES ...
Page 593: ...I O PORTS S3C2500B 15 12 NOTES ...