EM639165
BASIC FUNCTIONS
The EM639165 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 opt ion, 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
Command
Refresh Option @ refresh command
Precharge Option @ precharge or read/write command
define basic 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 deac-
tivated 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 including bank address
are generated internally. After this command, the banks are precharged automatically.
Preliminary
4
Rev 1.0
Feb. 2001
ETRON [ ETRON TECHNOLOGY, INC. ]
