RA8835A
Version 1.0
Dot Matrix LCD Controller
7-8 Reset
VDD
10*tc reset
pulse
0.7VDD
RES
0.3VDD
Figure 7-8: Reset Timing
The RA8835A series requires a reset pulse at least 10*tc long after power-on in order to re-initialize its
internal state. If the oscillator frequency is 10Mhz, then the Reset pulse is at least 1µs. For maximum
reliability, it is not recommended to apply a DC voltage to the LCD panel while the RA8835A series is
reset. Turn off the LCD power supplies for at least one frame period after the start of the reset pulse.
The RA8835A series 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 3 ms (maximum) is required following the rising edges of both RES and VDD to
allow for system stabilization.
7-9 Character Configuration
The origin of each character bitmap is in the top left corner as shown in Figure 7-9. Adjacent bits in
each byte are horizontally adjacent in the corresponding character image. Although the size of the
bitmap is fixed by the character generator, the actual displayed size of the character field can be varied
in both dimensions.
Character start point
FX
D7
to
D0
R0
R1
R2
R3
R4
R5
R6
R7
0
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
1
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
1
0
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
Character
height
FY
R8
R9
R10
R11
R12
R13
R14
R15
Space
data
Space
Character Space
width data
Space
data
Figure 7-9: Example of Character Display ([FX] ≤ 8) and Generator Bitmap
If the area outside the character bitmap contains only zeros, the displayed character size can easily be
increased by increasing FX and FY, as the zeros ensure that the extra space between displayed
characters is blank. The displayed character width can be set to any value up to 16 even if each
horizontal row of the bitmap is two bytes wide.
RAiO TECHNOLOGY INC.
www.raio.com.tw
40/88
RAIO [ RAIO TECHNOLOGY INC. ]
