Harman Kardon AVR 254, Service Manual

Page: 105 / 189

8
Revision 1.9
256M Double Data Rate Synchronous DRAM
A3S56D30ETP
A3S56D40ETP
COMMAND TRUTH TABLE
COMMAND MNEMONIC
CKE
n-1
CKE
n
/CS /RAS /CAS /WE BA0,1
A10
/AP
A0-9,
11-12
Deselect
DESEL H X H X X X X X X
No Operation
NOP H X L H H H X X X
Row Address Entry &
Bank Activate
ACT H H L L H H V V V
Single Bank Precharge
PRE H H L L H L V L X
Precharge All Banks
PREA H H L L H L H X
Column Address Entry
& Write
WRITE H H L H L L V L V
Column Address Entry
& Write with
Auto-Precharge
WRITEA H H L H L L V H V
Column Address Entry
& Read
READ H H L H L H V L V
Column Address Entry
& Read with
Auto-Precharge
READA H H L H L H V H V
Auto-Refresh REFA H H L L L H X X X
Self-Refresh Entry REFS H L L L L H X X X
Self-Refresh Exit REFSX
L H H X X X X X X
L H L H H H X X X
Burst Terminate TERM H H L H H L X X X
Mode Register Set MRS H H L L L L L L V
X
note
1
2
H=High Level, L=Low Level, V=Valid, X=Don't Care, n=CLK cycle number
NOTE:
1. Applies only to read bursts with autoprecharge disabled; this command is undefined (and should not be used) for
read bursts with autoprecharge enabled, and for write bursts.
2. BA0-BA1 select either the Base or the Extended Mode Register (BA0 = 0, BA1 = 0 selects Mode Register;BA0=1 ,
BA1 = 0 selects Extended Mode Register; other combinations of BA0-BA1 are reserved; A0-A12 provide the
op-code to be written to the selected Mode Register.
105
AVR254
harman/kardon