msm548262 Oki Semiconductor, msm548262 Datasheet - Page 35

• Manufacturer Part Number: msm548262
• Description: 262,144-word 8-bit Multiport Dram
• Manufacturer: Oki Semiconductor

Split Data Transfer and QSF
The MSM548262 features a bidirectional split data transfer capability between the RAM and
Split Read Transfer: RAS falling edge --- CAS = WE = DSF = "H", TRG = "L"
Split read transfer consists of loading 256 words by 8 bits of data from a selected row of the split
Conventional (non-split) read transfer operation must precede split read transfer cycles.
Masked Split Write Transfer: RAS falling edge --- CAS = DSF = "H", TRG = WE ="L"
Split write transfer consists of loading 256 words by 8 bits of data from the non-active split SAM
A split write transfer can be performed after a delay of t
A masked write transfer operation must precede split write transfer. The purpose is to switch the
POWER UP
Power must be applied to the RAS and TRG input signals to pull them "high" before, or at the
(NOTE) INITIAL STATE AFTER POWER UP
The initial state can not be guaranteed for various power up conditions and input signal levels.
¡ Semiconductor
SAM. During split data transfer operation, the serial register is split into two halves which can
be controlled independently. Split read or split write transfer operation can be performed to or
from one half of the serial register, while serial data can be shifted into or out of the other half of
the serial register. The most significant column address location (A8C) is controlled internally to
determines which half of the serial register will be reloaded from the RAM. QSF is an output
which indicates which half of the serial register is in an active state. QSF changes state when the
last SC clock is applied to active split SAM.
RAM into the corresponding non-active split SAM register. Serial data can be shifted out from
the other half of the split SAM register simultaneously. During split read transfer operation, the
RAM port input clocks do not have to be synchronized with the serial clock SC, thus eliminating
timing restrictions as in the case of real time read transfers. A split read transfer can be performed
after a delay of t
register into a selected row of the corresponding split RAM. Serial data can be shifted into the
other half of the split SAM register simultaneously. During split write transfer operation, the
RAM port input clocks do not have to be synchronized with the serial clock SC, thus allowing
for real time transfer. This write transfer operation, which is the same as a mask write operation
in RAM, can be selectively controlled for 8 DQis by inputing the mask data from DQ1 - DQ8 at
the falling edge of RAS.
output is satisfied.
SAM port from output mode to input mode, and to set the initial TAP location prior to split write
transfer operations.
same time as, the V
required with RAS and TRG held "high". After the pause, a minimum of 8 RAS and 8 SC dummy
cycles must be performed to stabilize the internal circuitry, before valid read, write or transfer
operations can begin. During the initialization period, the TRG signal must be held "high". If the
internal refresh counter is used, a minimum 8 CAS before RAS cycles are required instead of 8
RAS cycles.
Therefore, it is recommended that the initial state be set after the initialization of the device is
performed and before valid operations begin.
STS
from the change of state of the QSF output is satisfied.
CC
supply is turned on. After power-up, a pause of 200 ms minimum is
STS
from the change of state of the QSF
MSM548262
35/37