ra8802 RAIO Technology Inc., ra8802 Datasheet - Page 22

• Manufacturer Part Number: ra8802
• Description: Character/graphic Lcd Controller
• Manufacturer: RAIO Technology Inc.

Version 1.3
RAiO
6.8 DAC
6.9 ADC
6.10 Interrupt and Busy Flag
TECHNOLOGY INC.
RA8802/8820 is built-in one 5-bit fixed current type Digital-to-Analog Converter (D/A). Because DAC will
generate different current output, users can make use of it to control external boost circuit and let the
voltage level which supply to LCD Panel will be changed by different setup of DAC. Then users can use
program to control the brightness of LCD through MCU.
The RA8802/8820 built in 8 Bit ADC and control circuits to easily interface to 4-write analog resistive
touch screens. The RA8802/8820 continually monitors the screen waiting for a touch. When the screen is
touched, the RA8802/8820 performs analog to digital conversion to determine the location of the touch,
stores the X and Y locations in the registers, and can issues an interrupt.
RA8802
RA8820
Figure 6-5: Application Circuit of Touch Panel
Figure 6-6: Touch Panel and detection switch
VREF
VCC
X1
X2
Y1
Y2
Iref
30pF
SW0
2.3K
XL
SW2
SW3
VCC
22/22
YU
YD
Resistor-Y
Resistor-X
GND
XR
SW1
20pF
Touch Panel
XL
XR
YU
YD
Character/Graphic LCD Controller
RA8802/8820
www.raio.com.tw