HYB18M1G16 Datasheet, PDF (29/65 Pages) Qimonda AG – 1-Gbit x16 DDR Mobile-RAM

Data Sheet
HY[B/E]18M1G16[0/1]BF
1-Gbit DDR Mobile-RAM
2.4.5.2 READ to WRITE
Data from any READ burst must be completed or truncated before a subsequent WRITE command can be issued. If truncation
is necessary, the BURST TERMINATE command must be used, as shown in Figure 19.
CK
CK
Command
Address
READ
BA,Col n
DQS
DQ
DM
BST
CL=2
NOP
DO n
WRITE
BA,Col b
t_DQSS
NOP
Di b
FIGURE 19
READ to WRITE
NOP
Command
Address
READ
BA,Col n
DQS
DQ
DM
BST
NOP
NOP
CL=3
DO n
WRITE
BA,Col b
DO n = Data Out from column n; DI b = Data In to column b
1 subsequent element of Data Out appear in the programmed order following DO n.
Data In elements are applied following DI b in the programmed order
NOP
Di b
= Don't Care
2.4.5.3 READ to PRECHARGE
A READ burst may be followed by, or truncated with a PRECHARGE command to the same bank (provided that Auto
Precharge was not activated).
The PRECHARGE command should be issued x clock cycles after the READ command, where x equals the number of desired
data element pairs. This is shown in Figure 20. Following the PRECHARGE command, a subsequent command to the same
bank cannot be issued until t_RP is met. Please note that part of the row precharge time is hidden during the access of the last
data elements.
In the case of a READ being executed to completion, a PRECHARGE command issued at the optimum time (as described
above) provides the same operation that would result from the same READ burst with Auto Precharge enabled. The
disadvantage of the PRECHARGE command is that it requires that the command and address busses be available at the
appropriate time to issue the command. The advantage of the PRECHARGE command is that it can be used to truncate bursts.
Rev.1.0, 2007-03
29
10242006-Y557-TZXW