ra8835 Topway Display, ra8835 Datasheet - Page 9

• Manufacturer Part Number: ra8835
• Description: Dot Matrix Lcd Controller
• Manufacturer: Topway Display

RAiO TECHNOLOGY INC.
Version 1.7
5-1-3 LCD Drive Signals
5-1-4 Oscillator and Power
In order to provide effective low-power drive for LCD matrixes, the RA8835 series can directly
control both the X- and Y-drivers using an enable chain.
Note: The peak supply current drawn by the RA8835 series may be up to ten times the average
XD0 to
Name
Name
XSCL
XECL
YSCL
TEST
YDIS
GND
VDD
XD3
Pin
WF
Pin
YD
XG
XD
LP
supply current. The power supply impedance must be kept as low as possible by ensuring
that supply lines are sufficiently wide and by placing 0.47μF decoupling capacitors that have
Data Output for Driver.
4-bit X-driver (column drive) data outputs. Connect these outputs to the inputs of the
X-driver chips.
Latch Clock.
The falling edge of XSCL latches the data on XD0 to XD3 into the input shift registers
of the X-drivers. To conserve power, this clock halts between LP and the start of the
following display line (See section 6-3-7).
Trigger Clock for Chain Cascade.
The falling edge of XECL triggers the enable chain cascade for the X-drivers. Every
16th clock pulse is output to the next X-driver.
Latch Pulse.
LP latches the signal in the X-driver shift registers into the output data latches. LP is a
falling-edge triggered signal, and pulses once every display line.
Connect LP to the Y-driver shift clock on modules.
AC Drive Output.
The WF period is selected to be one of two values with SYSTEM SET command.
Latch Clock for YD.
The falling edge of YSCL latches the data on YD into the input shift registers of the Y-
drivers. YSCL is not used with driver ICs that use LP as the Y-driver shift clock.
Data Pulse Output for Y Drivers.
It is active during the last line of each frame, and is shifted through the Y drivers one
by one (by YSCL), to scan the display’s common connections.
Power-down Output Signal.
YDIS is HIGH while the display drive outputs are active. YDIS goes LOW one or two
frames after the sleep command is written to the RA8835 series. All Y-driver outputs
are forced to an intermediate level (de-selecting the display segments) to blank the
display. In order to implement power-down operation in the LCD unit, the LCD power
drive supplies must also be disabled when the display is disabled by YDIS.
Crystal Connection for Internal Oscillator
This pin can be driven by an external clock source that satisfies the timing
specifications of the EXT f0 signal (See section 7-3-6).
Crystal Connection for Internal Oscillator
Leave this pin open when using an external clock source.
2.7 to 5.5V Supply.
This may be the same supply as the controlling microprocessor.
Ground
Test Pin.
This is a test pins. No need for connection(NC).
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Function
Function
Dot Matrix LCD Controller
www.raio.com.tw
RA8835