msm5416273 Oki Semiconductor, msm5416273 Datasheet - Page 36

• Manufacturer Part Number: msm5416273
• Description: 262,144-word 16-bit Multiport Dram
• Manufacturer: Oki Semiconductor

¡ Semiconductor
Read Transfer: RAS falling edge --- CAS = WE = "H", TRG = DSF = "L"
Read transfer consists of loading a selected row of data from the RAM into the SAM register. A
read transfer is invoked by holding CAS "high", TRG "low", WE "high", and DSF "low" at the
falling edge of RAS. The row address selected at the falling edge of RAS determines the RAM row
to be transferred into the SAM. The transfer cycle is completed at the rising edge of TRG. When
the transfer is completed, the SAM port is set into the output mode. In a read/real time read
transfer cycle, the transfer of a new row of data is completed at the rising edge of TRG, and this
data becomes valid on the SDQ lines after the specified access time t
the subsequent SC cycles. The start address of the serial pointer of the SAM is determined by the
column address selected at the falling edge of CAS. In a read transfer cycle (which is preceded
by a write transfer cycle), SC clock must be held at a constant V
has been satisfied. A rising edge of the SC clock must not occur until after the specified delay t
from the rising edge of TRG.
In a real time read transfer cycle (which is preceded by another read transfer cycle), the previous
row data appears on the SQD lines until the TRG signal goes "high", and the serial access time
t
of data to appear on the serial output as soon as the last bit of the previous row has been strobed
without any timing loss. To make this continuous data flow possible, the rising edge of TRG must
be synchronized with RAS, CAS, and the subsequent rising edge of SC (t
must be satisfied).
Masked Write Transfer: RAS falling edge --- CAS = "H", TRG = DSF = "L"
Write transfer cycle consists of loading the content of the SAM register into a selected row of the
RAM. This write transfer is the same as a mask write operation in RAM, so new and persistent
(old) mask modes can be supported. (Masked write transfer)
If the SAM data to be transferred must first be loaded through the SAM, a Masked write transfer
operation (all DQ pins "low" at falling edge of RAS) must precede the write transfer cycles. A
masked write transfer is invoked by holding CAS "high", TRG "low", WE "low", and DSF "low"
at the falling edge of RAS. The row address selected at the falling edge of RAS determines the
RAM row address into which the data will be transferred. The column address selected at the
falling edge of CAS determines the start address of the serial pointer of the SAM. After the write
transfer is completed, the SDQ lines are set in the input mode so that serial data synchronized
with the SC clock can be loaded.
When consecutive write transfer operations are performed, new data must not be written into
the serial register until the RAS cycle of the preceding write transfer is completed. Consequently,
the SC clock must be held at a constant V
clock is only allowed after the specified delay t
a new row of data can be written in the serial register.
Data transferred to SAM by read transfer cycle or split read transfer cycle can be written to the
other address of RAM by write transfer cycle. However, the address to write data must be the
same as that of the read transfer cycle (row address AX8).
SCA
for the following serial clock is satisfied. This feature allows for the first bit of the new row
IL
or V
CSD
IH
WE = "L"
from the falling edge of the CAS, at which time
during the RAS cycle. A rising edge of the SC
IL
or V
SCA
IH
RTH
from the rising edge of
after the SC high time
, t
FEDS5416273-05
CTH
MSM5416273
and t
TSL
36/41
/t
TSD
TSD