A43L8316AV AMICC [AMIC Technology], A43L8316AV Datasheet - Page 15

• Manufacturer Part Number: A43L8316AV
• Description: 128K X 16 Bit X 2 Banks Synchronous DRAM
• Manufacturer: AMICC [AMIC Technology]

Device Operations (continued)
Auto Precharge
The precharge operation can also be performed by using
auto precharge. The SDRAM internally generates the timing
to satisfy t
length and CAS latency. The auto precharge command is
issued at the same time as burst read or burst write by
asserting high on A8/AP. If burst read or burst write
command is issued with low on A8/AP, the bank is left
active until a new command is asserted. Once auto
precharge command is given, no new commands are
possible to that particular bank until the bank achieves idle
state.
Both Banks Precharge
Both banks can be precharged at the same time by using
Precharge all command. Asserting low on
t
At the end of tRP after performing precharge all, both banks
are in idle state.
Auto Refresh
The storage cells of SDRAM need to be refreshed every
16ms to maintain data. An auto refresh cycle accomplishes
refresh of a single row of storage cells. The internal counter
increments automatically on every auto refresh cycle to
refresh all the rows. An auto refresh command is issued by
asserting low on
and
with both banks being in idle state and the device is not in
power down mode (CKE is high in the previous cycle). The
time required to complete the auto refresh
(September, 2003, Version 1.0)
WE
RAS
(min) requirement, performs precharge on both banks.
WE
with high on A8/AP after both banks have satisfied
. The auto refresh command can only be asserted
RAS
(min) and “t
CS
,
RAS
RP
” for the programmed burst
and
CAS
with high on CKE
CS
,
RAS
and
14
operation is specified by “t
of clock cycles required can be calculated by driving “t
with clock cycle time and then rounding up to the next
higher integer. The auto refresh command must be followed
by NOP’s until the auto refresh operation is completed.
Both banks will be in the idle state at the end of auto
refresh operation. The auto refresh is the preferred refresh
mode when the SDRAM is being used for normal data
transactions. The auto refresh cycle can be performed once
in 15.6us or a burst of 1024 auto refresh cycles once in
16ms.
Self Refresh
The self refresh is another refresh mode available in the
SDRAM. The self refresh is the preferred refresh mode for
data retention and low power operation of SDRAM. In self
refresh mode, the SDRAM disables the internal clock and
all the input buffers except CKE. The refresh addressing
and timing is internally generated to reduce power
consumption.
The self refresh mode is entered from all banks idle state
by asserting low on
on WE . Once the self refresh mode is entered, only CKE
state being low matters, all the other inputs including clock
are ignored to remain in the self refresh.
The self refresh is exited by restarting the external clock
and then asserting high on CKE. This must be followed by
NOP’s for a minimum time of “t
reaches idle state to begin normal operation. If the system
uses burst auto refresh during normal operation, it is
recommended to used burst 1024 auto refresh cycles
immediately after exiting self refresh.
CS
AMIC Technology, Corp.
,
RAS
RC
(min)”. The minimum number
,
CAS
RC
” before the SDRAM
A43L8316A
and CKE with high
RC
”