256Mb: x4, x8, x16 SDRAM
Commands
READ
The READ command is used to initiate a burst read access to an active row. The values
on the BA0 and BA1 inputs select the bank; the address provided selects the starting col-
umn location. The value on input A10 determines whether auto precharge is used. If au-
to precharge is selected, the row being accessed is precharged at the end of the READ
burst; if auto precharge is not selected, the row remains open for subsequent accesses.
Read data appears on the DQ subject to the logic level on the DQM inputs two clocks
earlier. If a given DQM signal was registered HIGH, the corresponding DQ will be High-
Z two clocks later; if the DQM signal was registered LOW, the DQ will provide valid data.
Figure 15: READ Command
CLK
CKE
HIGH
CS#
RAS#
CAS#
WE#
Column address
EN AP
Address
1
A10
DIS AP
BA0, BA1
Bank address
Don’t Care
1. EN AP = enable auto precharge, DIS AP = disable auto precharge.
Note:
PDF: 09005aef8091e6d1
256Mb_sdr.pdf - Rev. R 10/12 EN
Micron Technology, Inc. reserves the right to change products or specifications without notice.
© 1999 Micron Technology, Inc. All rights reserved.
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