Basic Functions - Harman Kardon AVR354 Service Manual

AVR354

BASIC FUNCTIONS

The A3S56D30/40ETP 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
CLK
/CS
/RAS
/CAS
/WE
CKE
A10
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 including bank address are generated
internally. After this command, the banks are precharged automatically.
256M Double Data Rate Synchronous DRAM
Chip Select : L=select, H=deselect
Command
Command
define basic commands
Command
Refresh Option @refresh command
Precharge Option @precharge or read/write command
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harman/kardon
A3S56D30ETP
A3S56D40ETP