HYB25DC512800B Datasheet, PDF (19/35 Pages) Qimonda AG – 512-Mbit Double-Data-Rate SDRAM

Internet Data Sheet
HYB25DC512[80/16]0B[E/F]
Double-Data-Rate SDRAM
TABLE 16
Truth Table 4: Current State Bank n - Command to Bank m (different bank)
Current State
CS RAS CAS WE Command
Action
Note
Any
H X X X Deselect
NOP. Continue previous operation.
1)2)3)4)5)6)
L H H H No Operation
NOP. Continue previous operation.
1) to 6)
Idle
X X X X Any Command —
Otherwise
Allowed to Bank
m
1) to 6)
Row Activating, L L H H Active
Active, or
Precharging
L H L H Read
L H L L Write
Select and activate row
Select column and start Read burst
Select column and start Write burst
1) to 6)
1) to 7)
1) to 7)
L L H L Precharge
—
1) to 6)
Read (Auto
Precharge
Disabled)
L L H H Active
L H L H Read
L L H L Precharge
Select and activate row
Select column and start new Read burst
—
1) to 6)
1) to 7)
1) to 6)
Write (Auto
Precharge
Disabled)
L L H H Active
L H L H Read
L H L L Write
Select and activate row
Select column and start Read burst
Select column and start new Write burst
1) to 6)
1) to 8)
1) to 7)
L L H L Precharge
—
1) to 6)
Read (With Auto L L H H Active
Precharge)
L H L H Read
Select and activate row
Select column and start new Read burst
1) to 6)
1) to 7), 9)
L H L L Write
Select column and start Write burst
1) to 7), 9), 10)
L L H L Precharge
—
1) to 6)
Write (With Auto L L H H Active
Precharge)
L H L H Read
Select and activate row
Select column and start Read burst
1) to 6)
1) to 7), 9)
L H L L Write
Select column and start new Write burst
1) to 7), 9)
L L H L Precharge
—
1) to 6)
1) This table applies when CKE n-1 was HIGH and CKE n is HIGH (see Table 14: Clock Enable (CKE) and after t_XSNR/t_XSRD has been met
(if the previous state was self refresh).
2) This table describes alternate bank operation, except where noted, i.e., the current state is for bank n and the commands shown are those
allowed to be issued to bank m (assuming that bank m is in such a state that the given command is allowable). Exceptions are covered in
the notes below.
3) Current state definitions:
Idle: The bank has been precharged, and t_RP has been met.
Row Active: A row in the bank has been activated, and t_RCD 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.
Read with Auto Precharge Enabled: See ¹⁰⁾.
Write with Auto Precharge Enabled: See ¹⁰⁾.
4) AUTO REFRESH and Mode Register Set commands may only be issued when all banks are idle.
5) A BURST TERMINATE command cannot be issued to another bank; it applies to the bank represented by the current state only.
6) All states and sequences not shown are illegal or reserved.
7) 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.
8) Requires appropriate DM masking.
Rev. 1.2, 2007-04
19
04112007-FHBX-O8HD