ra8806 RAIO Technology Inc., ra8806 Datasheet - Page 60

• Manufacturer Part Number: ra8806
• Description: Two Layers Character/graphic Lcd Controller
• Manufacturer: RAIO Technology Inc.

Preliminary Version 1.2
RAiO
TECHNOLOGY INC.
6-6-3 Reset
The RA8806 requires a reset pulse at least 1024*tc long after power-on in order to re-initialize its
internal state. If the oscillator frequency is 6Mhz, then the Reset pulse is at least 170.7µs. For
maximum reliability, it is not recommended to apply a DC voltage to the LCD panel while the
RA8806 is reset. Turn off the LCD power supplies for at least one frame period after the start of the
reset pulse.
Figure 6-27 is an example for ZRST application circuit. It could be controlled by MPU such as (1) of
Figure 6-27. Or, generated by a RC circuit such as (2) of Figure 6-27.
The RA8806 cannot receive commands while it is reset. Commands to initialize the internal registers
should be issued soon after a reset. During reset, the LCD drive signals XD, LP and FR are halted.
A delay of 1ms (minimum) is required following the rising edges of both ZRST and VDD to allow for
system stabilization. Please refer to Figure 6-28 for more detail description.
ZRST
VDD
From MCU
0.8VDD
0.1uF
*t
for example: 10MHz, t
C
0.8VDD
t
t
t
is the period of system clock,
RST
RS
RH
t
Figure 6-27: Examples of ZRST Pin
RS
0.2VDD
Reset active time
Reset setup time
Figure 6-28: Reset Timing
ZRST
Reset hold time
RA8806
(1)
t
C
RST
= 100ns
60/184
Max.
--
--
--
(Option)
Two Layers Character/Graphic LCD Controller
SW
100KΩ
Typ.
--
--
--
1uF
VDD
1024
Min.
1
1
t
RH
ZRST
t
Unit
c
ms
ms
RA8806
(*)
(2)
Reset Complete
www.raio.com.tw
RA8806