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CONFIDENTIAL – DO NOT COPY
Page 8-43
File No. SG-0184
Truth Table a: Commands
1. CKE is high for all commands shown except Self Refresh.
2. BA0, BA1 select either the Base or the Extended Mode Register (BA0 = 0, BA1 = 0 selects
Mode Register; BA0 = 1, BA1 = 0 selects ,Extended Mode Register; other combinations of
BA0-BA1 are reserved; A0-A12 provide the op-code to be written to the selected Mode
Register.)
3. BA0-BA1 provide bank address and A0-A12 provide row address.
4. BA0, BA1 provide bank address; A0-Ai provide column address (where i = 9 for x8 and 9, 11
for x4); A10 high enables the Auto Precharge feature (non-persistent), A10 low disables the
Auto Precharge feature.
5. A10 LOW: BA0, BA1 determine which bank is precharged.A10 HIGH: all banks are
precharged and BA0, BA1 are “Don’t Care.”
6. This command is auto refresh if CKE is high; Self Refresh if CKE is low.
7. Internal refresh counter controls row and bank addressing; all inputs and I/Os are “Don’t Care”
except for CKE.
8. Applies only to read bursts with Auto Precharge disabled; this command is undefined (and
should not be used) for read bursts with Auto Precharge enabled or for write bursts
9. Deselect and NOP are functionally interchangeable.
Active
The Active command is used to open (or activate) a row in a particular bank for a subsequent
access. The value on the BA0,BA1 inputs selects the bank, and the address provided on inputs
A0-A12 selects the row. This row remains active (or open) for accesses until a Precharge (or
Read or Write with Auto Precharge) is issued to that bank. A Precharge (or Read or Write with
Auto Precharge) command must be issued and completed before opening a different row in the
same bank.
Read
The Read command is used to initiate a burst read access to an active (open) row. The value on
the BA0, BA1 inputs selects the bank, and the address provided on inputs A0-Ai, Aj (where [i = 9,
j = don’t care] for x8; where [i = 9, j = 11] for x4) selects the starting column location. The value
on input A10 determines whether or not Auto Precharge is used. If Auto 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.