M2V56S20AKT Datasheet, PDF (5/49 Pages) Mitsubishi Electric Semiconductor – 256M Synchronous DRAM

SDRAM (Rev.1.01)
Single Data Rate
MITSUBISHI LSIs
M2V56S20/ 30/ 40 AKT -5, -6, -7
July '01
256M Synchronous DRAM
BASIC FUNCTIONS
The M2V56S20/30/40AKT provides basic functions, bank (row) activate, burst read / write, bank (row)
precharge, and auto / self refresh. Each command is defined by control signals of /RAS, /CAS and /WE at
CLK rising edge. In addition to 3 signals, /CS ,CKE and A10 are used as chip select, refresh option, and
precharge option, respectively. To know the detailed definition of commands, please see the command
truth table.
CLK
/CS
/RAS
/CAS
/WE
CKE
A10
Chip Select : L=select, H=deselect
Command
Command define basic commands
Command
Refresh Option @refresh command
Precharge Option @precharge or read/write command
Activate (ACT) [/RAS =L, /CAS =/WE =H]
ACT command activates a row in an idle bank indicated by BA.
Read (READ) [/RAS =H, /CAS =L, /WE =H]
READ command starts burst read from the active bank indicated by BA. First output data appears after
/CAS latency. When A10 =H at this command, the bank is deactivated after the burst read (auto-
precharge, READA)
Write (WRITE) [/RAS =H, /CAS =/WE =L]
WRITE command starts burst write to the active bank indicated by BA. Total data length to be written
is set by burst length. When A10 =H at this command, the bank is deactivated after the burst write
(auto-precharge, WRITEA).
Precharge (PRE) [/RAS =L, /CAS =H, /WE =L]
PRE command deactivates the active bank indicated by BA. This command also terminates burst read
/write operation. When A10 =H at this command, all banks are deactivated (precharge all, PREA).
Auto-Refresh (REFA) [/RAS =/CAS =L, /WE =CKE =H]
REFA command starts auto-refresh cycle. Refresh address are generated internally. After this
command, the banks are precharged automatically.
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