RA8835A
Version 1.0
Dot Matrix LCD Controller
7-6 Oscillator Circuit
The RA8835A series incorporates an oscillator circuit. A stable oscillator can be constructed simply by
connecting an AT-cut crystal and two capacitors to XG and XD, as shown in the figure below. If the
oscillator frequency is increased, CD and CG should be decreased proportionally. Note that the circuit
board lines to XG and XD must be as short as possible to prevent wiring capacitance from changing
the oscillator frequency or increasing the power consumption.
RA8835
XG
XD
CD=3 to 20 pF
CG=2 to 18 pF
CG
CD
Load impedance =700? (max)
Figure 7-4: Crystal Oscillator
7-7 Status Flag
The RA8835A series has a single bit status flag.
D6: X line standby
Figure 7-5: Status Flag
The D6 status flag is HIGH for the TC/R-C/R cycles at the end of each line where the RA8835A series
is not reading the display memory. The microprocessor may use this period to update display memory
without affecting the display, however it is recommended that the display be turned off when refreshing
the whole display.
LP
tTC/R
tm
tC/R
XSCL
Figure 7-6: C/R to TC/R Time Difference
RAiO TECHNOLOGY INC.
www.raio.com.tw
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RAIO [ RAIO TECHNOLOGY INC. ]
