RA8835A
Version 1.0
Dot Matrix LCD Controller
6-2-1-7 FX
Define the horizontal character size. The character width in pixels is equal to FX + 1, where FX can
range from 00 to 07H inclusive. If data bit 3 is set (FX is in the range 08 to 0FH) and an 8-pixel font
is used, a space is inserted between characters.
Table-3: Horizontal Character Size Selection
FX
[FX] character
width (pixels)
D
3
0
0
↓
D
2
0
0
↓
D
1
0
0
↓
D
0
0
1
↓
HEX
00
01
↓
1
2
↓
8
07
0
1
1
1
Since the RA8835A series handles display data in 8-bit units, characters larger than 8 pixels wide
must be formed from 8-pixel segments. As Figure 6-6 shows, the remainder of the second eight
bits are not displayed. This also applies to the second screen layer.
In graphics mode, the normal character field is also eight pixels. If a wider character field is used,
any remainder in the second eight bits is not displayed.
FX
FX
8 bits
8 bits
8 bits
8 bits
Non-display area
Address A
Address B
Figure 6-6: FX and FY Display Addresses
6-2-1-8 WF
Select the AC frame drive waveform period. WF is usually set to 1.
WF = 0: 16-line AC drive
WF = 1: two-frame AC drive
In two-frame AC drive, the WF period is twice the frame period.
In 16-line AC drive, WF inverts every 16 lines.
Although 16-line AC drive gives a more readable display, horizontal lines may appear when using
high LCD drive voltages or at high viewing angles.
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