SMJ44C251B Datasheet, PDF (48/53 Pages) Texas Instruments – 262144 BY 4-BIT MULTIPORT VIDEO RAM

SMJ44C251B
262144 BY 4-BIT
MULTIPORT VIDEO RAM
SGMS058A – MARCH 1995 – REVISED JUNE 1995
PARAMETER MEASUREMENT INFORMATION
RAS
tsu( _TRG)
th( _TRG)
TRG
SC
tw(SCH)
tc(SC)
tw(SCL)
tsu(SDS)
th(SDS)
tc(SC)
tw(SCH)
tw(SCL)
tsu(SDS)
th(SDS)
tw(SCH)
tsu(SDS)
th(SDS)
SDQ0 – SDQ3
Valid In
Valid In
Valid In
NOTES: A. The serial data-in cycle is used to input serial data into the data registers. Before data can be written into the data registers via the
SDQ terminals, the device must be put into the write mode by performing a write-mode-control (pseudo-transfer) cycle or any other
write-transfer cycle. A read-transfer cycle is the only cycle that takes the serial port (SAM) out of the write mode and puts it into the
read mode, disabling the input data. Data is written starting at the location specified by the input address loaded on the previous
transfer cycle.
B. While accessing data in the serial-data registers, the state of TRG is a don’t care as long as TRG is held high when RAS goes low
to prevent data transfers between memory and data registers.
Figure 36. Serial-Write-Cycle Timing (SE = V_IL )
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