W949D6CB Datasheet, PDF (22/60 Pages) Winbond – 512Mb Mobile LPDDR

W949D6CB / W949D2CB
6.11.5 Truth Table - Current State BANKn - Command to BANKn
512Mb Mobile LPDDR
CURRENT STATE _{CS RAS CAS WE} COMMAND
ACTION
NOTES
H X X X DESELECT
NOP or Continue previous operation
Any
L H H H No Operation
NOP or Continue previous operation
L L H H ACTIVE
Select and activate row
Idle
L L L H AUTO REFRESH Auto refresh
10
L L L L MRS
Mode register set
10
L H L H READ
Select column & start read burst
Row Active
L H L L WRITE
Select column & start write burst
L L H L PRECHARGE
Deactivate row in bank (or banks)
4
L H L H READ
Select column & start new read burst 5, 6
L H L L WRITE
Read (Auto precharge
Disabled)
L L H L PRECHARGE
L
H
H
L
BURST
TERMINATE
Select column & start write burst
Truncate read burst, start precharge
Burst terminate
5, 6, 13
11
L H L H READ
Write (Auto precharge
Disabled)
L
H
L L WRITE
L L H L PRECHARGE
Select column & start read burst
Select column & start new write burst
Truncate write burst & start precharge
5, 6, 12
5, 6
12
Notes:
1. The table applies when both CKEn-1 and CKEn are HIGH, and after tXSR or tXP has been met if the previous state was
Self Refresh or Power Down.
2. DESELECT and NOP are functionally interchangeable.
3. All states and sequences not shown are illegal or reserved.
4. This command may or may not be bank specific. If all banks are being precharged, they must be in a valid state for
precharging.
5. A command other than NOP should not be issued to the same bank while a READ or WRITE burst with Auto Precharge is
enabled.
6. The new Read or Write command could be Auto Prechrge enabled or Auto Precharge disabled.
7. Current State Definitions:
Idle: The bank has been precharged, and tRP has been met.
Row Active: A row in the bank has been activated, and tRCD has been met. No data bursts/accesses and no register
accesses are in progress.
Read: A READ burst has been initiated, with Auto Precharge disabled, and has not yet terminated or been terminated.
Write: A WRITE burst has been initiated, with Auto Precharge disabled, and has not yet terminated or been terminated.
8. The following states must not be interrupted by a command issued to the same bank. DESEDECT or NOP commands or
allowable commands to the other bank should be issued on any clock edge occurring during these states. Allowable
commands to the other bank are determined by its current state and this table, and according to next table.
Precharging: Starts with the registration of a PRECHARGE command and ends when tRP is met. Once tRP is met, the
bank will be in the idle state.
Row Activating: Starts with registration of an ACTIVE command and ends when tRCD is met. Once tRCD is met, the bank
will be in the „row active‟ state.
Read with AP Enabled: Starts with the registration of the READ command with Auto Precharge enabled and ends when
tRP has been met. Once tRP has been met, the bank will be in the idle state.
Write with AP Enabled: Starts with registration of a WRITE command with Auto Precharge enabled and ends when tRP has
been met. Once tRP is met, the bank will be in the idle state.
9. The following states must not be interrupted by any executable command; DESEDECT or NOP commands must be applied
to each positive clock edge during these states.
Refreshing: Starts with registration of an AUTO REFRESH command and ends when tRFC is met. Once tRFC is met, the
LPDDR SDRAM will be in an „all banks idle‟ state.
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Publication Release Date: Sep, 21, 2011
Revision A01-007