Internet Data Sheet
HY[B/E]18M256[16/32]0CF
256-Mbit DDR Mobile-RAM
Current State
CS
RAS CAS WE
Command / Action
Note
1)2)3)4)5)6)8)12)
Write (Auto-
Precharge
Disabled)
L
L
L
H
H
L
L
L
H
H
L
L
READ (truncate Write and start Read burst)
WRITE (truncate Write and start Write burst)
1)2)3)4)5)6)8)
1)2)3)4)5)6)9)12)
PRECHARGE (truncate Write burst, start Precharge)
1) This table applies when CKEn-1 was HIGH and CKEn is HIGH (see Table 7) and after tXP or tXSR has been met (if the previous state was
POWER-DOWN or SELF REFRESH).
2) This table is bank-specific, except where noted, i.e., the current state is for a specific bank and the commands shown are those allowed to
be issued to that bank when in that state. Exceptions are covered in the notes below.
3) 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.
4) The following states must not be interrupted by a command issued to the same bank. DESELECT 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 according to Table 7.Precharging: Starts with registration of a PRECHARGE command and ends
when tRP is met. Once tRP is met, the bank is 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 is in the “row active” state.Read with AP enabled: Starts with registration of a READ command
with Auto Precharge enabled and ends when tRP has been met. Once tRP is met, the bank is 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 is in the
idle state.
5) The following states must not be interrupted by any executable command; DESELECT or NOP commands must be applied on each
positive clock edge during these states.Refreshing: Starts with registration of an AUTO REFRESH command and ends when tRC is met.
Once tRC is met, the DDR Mobile-RAM is in the “all banks idle” state.Accessing Mode Register: Starts with registration of a MODE
REGISTER SET command and ends when tMRD has been met. Once tMRD is met, the DDR Mobile-RAM is in the “all banks idle”
state.Precharging All: Starts with registration of a PRECHARGE ALL command and ends when tRP is met. Once tRP is met, all banks are
in the idle state.
6) All states and sequences not shown are illegal or reserved.
7) Not bank-specific; requires that all banks are idle and no bursts are in progress.
8) Reads or Writes listed in the Command/Action column include Reads or Writes with Auto Precharge enabled and Reads or Writes with
Auto Precharge disabled.
9) May or may not be bank-specific; if multiple banks are to be precharged, each must be in a valid state for precharging.
10) A WRITE command may be applied after the completion of the Read burst; otherwise, a BURST TERMINATE command must be used to
end the Read burst prior to issuing a WRITE command.
11) Not bank-specific; BURST TERMINATE affects the most recent Read burst, regardless of bank.
12) Requires appropriate DM masking.
Rev.1.44, 2007-07
12
06262007-JK8G-48BV
QIMONDA [ QIMONDA AG ]
