RA8835A
Version 1.0
Dot Matrix LCD Controller
WR
or
R/
W
CS
Write Control or Read/Write Control.
When the 8080 family interface is selected, this signal acts as the active-LOW write
strobe. The bus data is latched on the rising edge of this signal.
When the 6800 family interface is selected, this signal acts as the read/write control
signal. Data is read from the RA8835A series if this signal is HIGH, and written to the
RA8835A series if it is LOW.
Chip Select.
This active-LOW input enables the RA8835A series. It is usually connected to the
output of an address decoder device that maps the RA8835A series into the memory
space of the controlling microprocessor.
Command/Data Select.
8080 Family Interface:
A0
0
1
0
1
RD
0
0
1
1
WR
1
1
0
0
A0
Function
Status flag read
Display data and cursor address read
Display data and parameter write
Command write
6800 Family Interface:
A0
0
1
0
1
R/
W
1
1
0
0
E
1
1
1
1
Function
Status flag read
Display data and cursor address read
Display data and parameter write
Command write
RES
Hardware Reset.
This active-LOW input performs a hardware reset on the RA8835A series. It is an
Schmitt-trigger input for enhanced noise immunity; however, care should be taken to
ensure that it is not triggered if the supply voltage is lowered.
5-1-2 Display Memory Control
The RA8835A series can directly access static RAM and PROM. The designer may use a mixture of
these two types of memory to achieve an optimum trade-off between low cost and low power
consumption.
Pin
Name
VA0 to
VA15
VD0 to
VD7
VWR
VRD
Function
16-bit Display Memory Address.
When accessing character generator RAM or ROM, VA0 to VA3, reflect the lower 4
bits of the RA8835A series’ row counter.
Display Memory Data Bus.
8-bit tristate display memory data bus. These pins are enabled when VR/
W
is LOW.
Display Memory Write Control.
Active-LOW display memory write control output.
Display Memory Read Control.
Active-LOW display memory read control output.
Display Memory Chip Select.
Active-LOW static memory standby control signal.
VCE
can be used with
CS
.
VCE
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