ra8835 Topway Display, ra8835 Datasheet - Page 55

• Manufacturer Part Number: ra8835
• Description: Dot Matrix Lcd Controller
• Manufacturer: Topway Display

8. Application Notes
RAiO TECHNOLOGY INC.
Version 1.7
8-1 Initialization Parameters
8-1-1 System Set Instruction and Parameters
The parameters for the initialization commands must be determined first. Square brackets around a
parameter name indicate the number represented by the parameter, rather than the value written to the
parameter register. For example, [FX] = FX + 1.
◎ FX
The horizontal character field size is determined from the horizontal display size in pixels [VD] and the
number of characters per line [VC].
◎ C/R
Where RND(x) denotes ´ rounded up to the next highest integer. [C/R] is the number of bytes per line,
not the number of characters.
◎ TC/R
◎ f
Once TC/R has been set, the frame frequency, f
The lower limit on the
◎ If no standard crystal close to the calculated value of f
used and the value of
◎ Symptoms of an incorrect TC/R setting are listed below. If any of these appears, check the value of
TC/R revised using the above equation.
• Vertical scanning halts and a high-contrast horizontal line appears.
• All pixels are on or off.
• The LP output signal is absent or corrupted.
• The display is unstable.
C/R can be determined from VC and FX.
TC/R and modify it if necessary.
TC/R must satisfy the condition
OSC
and resolution
Product name
f
[VD]
[VC]
[C/R]
and f
OSC
256 x 64
512 x 64
(X ´ Y)
≤
≥
=
FR
[FX]
RND(
(
[TC/R]
[FX]
8
×
Table-24: RAiO LCD Unit Example Parameters
[FX] = 6 pixels:
256 / 6 = 42
remainder 4 = 4
blank pixels
[FX] = 6 pixels:
512 / 6 = 85
)
9
×
oscillator frequency f
+
[VC]
1)
i d
×
[FX]
[L/F]
2
[TC/R]
×
2
f
FR
≥
8 or 16, depending
on the screen
8 or 16, depending
on the screen
[C/R]
55/86
OSC
+
is given by:
FR
4
[FY]
.
, and lines per frame [L/F] will also have been set.
OSC
exists, a higher frequency crystal can be
[C/R] = 42 = 2AH
bytes:
C/R = 29H. When
using HDOT SCR,
[C/R] = 43 bytes
[C/R] = 85 = 55H
bytes:
[C/R]
Dot Matrix LCD Controller
www.raio.com.tw
TC/R
2DH
58H
RA8835
See Note 2.
f
OSC
1.85
3.59
(MHz)