
IBM025170
IBM025171
256K X 16 MULTIPORT VIDEO RAM
IBM025160
IBM025161
IBM Corporation, 1995. All rights reserved.
Use is further subject to the provisions at the end of this document.
Page 4 of 65
33G0307
SA14-4751-05
Revised 3/98
DQ
0
- DQ
15
- Random Port Data Input/Output
In a Read cycle, these pins serve as outputs for the selected storage cells. In a Write cycle, data input on
these pins is latched by the falling edge of CE or LW/UW whichever occurs later. Data will not appear at the
outputs until after both CE and TRG have been brought low. During transfer operations, the DQ outputs
remain in the high-Z state for the entire cycle. In a Block Write cycle, data input on these pins is used to mask
the selected columns in the block. At RE falling edge, the data input at these pins can be used for loading the
Write-per-Bit Mask (WPBM).
SDQ
0
- SDQ
15
- Serial Port Data Input/Output
16 bit data can be written or read from these pins. The output data remains valid until the next SC clock is
activated.
SC - Serial Clock
The rising edge of the SC signal is used to initiate a Read/Write from/to the SAM Register (starting from the
location specified in the data transfer cycle). In the Serial Read mode, 16 of the 4096 data bits from the SAM
Register are transferred to 16 Serial Data Buses and read out. In the Serial Write operation, input data is
latched on the rising edge of SC clock. Whenever SC clock is low, the Serial port is in standby.
SE - Serial Port Enable
This signal enables or disables the Serial Input/Output buffer. When SE is high, the output of the Serial port is
in tri-state.
While SE is held high, the serial clock is not disabled. Thus, external SC pulses will incre-
ment 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 since the Serial Clock input buffer and
the Serial address counter are not disabled by SE.
V
cc
- (5.0V
±
0.5V) or (3.3V
±
0.3V) voltage.
All voltages are referenced to the nearest V
ss
pin.
V
ss
- Circuit ground. V
ss
= 0V.
NC - No Connect.
NC implies that the pin(s) should not be grounded or connected to any other signal. These pins might be used
for testing some modes at factory. Consult factory before using any one of NC pins.