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SMJ55166GB

262144 BY 16-BIT MULTIPORT VIDEO RAM

Austin Semiconductor 

SMJ55166

262144 BY 16-BIT

MULTIPORT VIDEO RAM

SGMS057C – APRIL 1995 – REVISED JUNE 1997

serial enable (SE)

During serial-access operations, SE enables/disables the SQ outputs. SE low enables the serial-data output

while SE high disables the serial-data output. SE is also used as an enable/disable for output pin QSF.

NOTE:While SE is held high, the serial clock is not disabled. External SC pulses increment the

internal serial-address counter, regardless of the state of SE. This ungated serial-clock scheme

minimizes access time of serial output from SE low because the serial-clock input buffer and the

serial-address counter are not disabled by SE.

special-function output (QSF)

QSF is an output pin that indicates which half of the SAM is being accessed. When QSF is low, the serial-address

pointer accesses the lower (least significant) 128 bits of the SAM. When QSF is high, the pointer accesses the

higher (most significant) 128 bits of the SAM. QSF changes state upon crossing a boundary between the two

SAM halves.

During full-register-transfer operations, QSF can change state upon completing the cycle. This state is

determined by the tap point loaded during the transfer cycle. QSF output is enabled by SE. If SE is high, the

QSF output is in the high-impedance state.

no connect/ground (NC/VSS)

NC/VSS must be tied to system ground or left floating for proper device operation.

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