k4h281638d Samsung Semiconductor, Inc., k4h281638d Datasheet - Page 18

• Manufacturer Part Number: k4h281638d
• Description: 128mb D-die X16 Ddr Sdram
• Manufacturer: Samsung Semiconductor, Inc.

128Mb D-die(x16) DDR SDRAM
mand is issued when CS, RAS and WE are low and CAS is high at the rising edge of the clock. The precharge
command can be used to precharge each bank respectively or all banks simultaneously. The bank select
addresses(BA0, BA1) are used to define which bank is precharged when the command is initiated. For write
cycle, tWR(min.) must be satisfied until the precharge command can be issued. After tRP from the precharge,
an active command to the same bank can be initiated.
3.2.3 Precharge
3.2.4 No Operation(NOP) & Device Deselect
all the control inputs. The DDR SDRAMs are put in NOP mode when CS is active and by deactivating RAS,
CAS and WE. For both Deselect and NOP the device should finish the current operation when this com-
mand is issued.
The precharge command is used to precharge or close a bank that has been activated. The precharge com-
The device should be deselected by deactivating the CS signal. In this mode DDR SDRAM should ignore
A10/AP
0
0
0
0
1
Table 5. Bank selection for precharge by Bank address bits
Bank Selection for Precharge by Bank address bits
BA1
0
0
1
1
X
- 18 -
BA0
X
0
1
0
1
REV. 0.6 Oct. 21. 2002
Bank A Only
Bank B Only
Bank C Only
Bank D Only
Precharge
All Banks