ra8802 RAIO Technology Inc., ra8802 Datasheet - Page 21

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

Version 1.3
RAiO
6.6 ROM
6.7 PLL/OSC Circuit
TECHNOLOGY INC.
The Figure 6-4 is the application circuit of clock. If select RC Oscillator mode, then pin XA, XB and LPF
should be floating. If X’tal and PLL mode is selected, then RA and RB should be floating.
setup the Register to change the size of the Display Panel.
RA8802/8820 embedded 512KByte Font ROM also provide external 512KByte Font ROM Interface can
use put the standard and special fonts of BIG5, GB, and ASCII code. It can support the display 16x16 dot
for full-size fonts consisting of Chinese, 8x16 dots for half-size fonts of alphanumeric characters and
symbols in the same display. For example, when MCU sends Big5 code (2 Bytes), RA8802/8820 will
read Font code (32 Bytes) from ROM, which is matching with Big5 code, and then deliver them to
DDRAM.
The internal system clock of RA8802/8820 is generated from the following way:
The pin SYS_FQ is for RA8802/8820 clock source selection. Non-Pull will enable internal PLL circuit and
X’tal will be the clock source of RA8802/8820. Pull low when RC oscillator is used and it will disable
internal PLL.
Note: The oscillator frequency can be adjusted by an oscillator resistor(Rf). If Rf is increased or power
supply voltage is decreased, the oscillator frequency decreases.
0.022u
2.7K
Use an external 32768Hz X’tal and internal PLL circuit
Use an external Resistor for internal RC-Oscillator
0.22 u
(1) Use X’tal and PLL
20p
20p
Figure 6-4 PLL & RC OSC Application Circuit
32768Hz
RA8802/8820
XA
XB
LPF
RA
RB
21/21
Rf
(2) Use RC-Oscillator
Character/Graphic LCD Controller
RA8802/8820
LPF
XA
XB
RA
RB
RA8802/8820
www.raio.com.tw