ra8835 Topway Display, ra8835 Datasheet - Page 40

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

RAiO TECHNOLOGY INC.
Version 1.7
7-10-2 Display Address Scanning
Note: One byte of display memory corresponds to one character.
The basic screen configuration of the RA8835 series is as a single text screen or as overlapping
text and graphics screens. The graphics screen uses eight times as much display memory as the
text screen. Figure 7-11 shows the relationship between the virtual screens and the physical
screen.
The RA8835 series scans the display memory in the same way as a raster scan CRT screen.
Each row is scanned from left to right until the address range equals C/R. Rows are scanned
from top to bottom.
In graphics mode, at the start of each line, the address counter is set to the address at the start of
the previous line plus the address pitch, AP.
In text mode, the address counter is set to the same start address, and the same character data
is read, for each row in the character bitmap. However, a new row of the character generator
output is used each time. Once all the rows in the character bitmap have been displayed, the
address counter is set to the start address plus AP and the next line of text is displayed.
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‧
‧
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2
3
1
SAD+2AP
SAD+AP
SAD
SAD+AP
SAD+1
WS=0,FX=8
16
17
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‧
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24
+1
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8
9
1
Figure 7-13: Character Parameters vs. Memory
SAD+2AP
Figure 7-12: Character Position Parameters
SAD+AP
SAD+AP
SAD
SAD+2
+2
C/R
SAD+AP
WS=0,FX=8,FY=8
SAD+1
+1
SAD+AP
SAD+2
+2
40/86
C/R
SAD+C/R
SAD+AP
+C/R
Line 2
Line 3
Line 1
SAD
SAD+1
SAD+2
SAD+C/R
SAD+AP
SAD+AP+1
SAD+AP+C/R
SAD+2AP
SAD+C/R
SAD+AP
+C/R
Dot Matrix LCD Controller
www.raio.com.tw
AP
AP
RA8835