97SD3240_06 Datasheet, PDF (15/39 Pages) Maxwell Technologies – 1.25Gb SDRAM 8-Meg X 40-Bit X 4-Banks

1.25Gb (8-Meg X 40-Bit X 4-Banks) SDRAM
97SD3240
To [ACTV]: This command makes the other bank active. ( However, an interval of t_RRD is required.)
Attempting to make the currently active bank active results in an illegal command.
To [PRE], [PALL]: These commands set the SDRAM to precharge mode. (However, an interval of t_RAS is
required.)
From READ state, command operation
To [DESL], [NOP]: These commands continue read operations until the operation is completed.
To [READ], [READ A]: Data output by the previous read command continues to be output. After CAS
latency, the data output resulting from the next command will start.
To [WRIT], [WRIT A]: These commands stop a burst read, and start a write cycle.
To [ACTV]: This command makes other banks bank active. (However,
Attempting to make the currently active bank active results in an illegal
an interval
command.
of
t_RRD
is
required.)
To [PRE], [PALL]: These commands stop a burst read, and the SDRAM enters precharge mode.
From READ with AUTO-PRECHARGE state, command operation
To [DESL], [NOP]: These commands continue read operations until the burst operation is completed, and
the SDRAM then enters precharge mode.
To [ACTV]: This command makes other banks active. (However, an interval of t_RRD is required.) Attempting
to make the currently active bank active results in an illegal command.
From WRITE state, command operation
To [DESL], [NOP]: These commands continue write operations until the burst operation is completed.
To [READ], [READ A]: These commands stop a burst and start a read cycle.
To [WRIT], [WRIT A]: These commands stop a burst and start the next write cycle.
To [ACTV]: This command makes the other bank active. (However, an interval of t_RRD is required.)
Attempting to make the currently active bank active results in an illegal command.
To [PRE], [PALL]: These commands stop burst write and the SDRAM then enters precharge mode.
From WRITE with AUTO-PRECHARGE state, command operation
To [DESL], [NOP]: These commands continue write operations until the burst is completed, and the
synchronous DRAM enters precharge mode.
To [ACTV]: This command makes the other bank active. (However, an interval of t_RRD is required.)
Attempting to make the currently active bank active result in an illegal command.
From REFRESH state, command operation
To [DESL], [NOP]: After an auto-refresh cycle (after t_RC) the SDRAM automatically enters the IDLE state.
05.10.06 Rev 4
All data sheets are subject to change without notice 15
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