HD66730 Datasheet, PDF (68/131 Pages) Hitachi Semiconductor – Dot-Matrix Liquid Crystal Display Controller/Driver Supporting Japanese Kanji, Korean Font Display

HD66730/HD66731
Status Register (ST)
The status register (Figure 5) includes the busy flag (BF), display line bits (NF1/0), and display raster-row
bits (LF0 to LF3). If BF is 1, an instruction is being executed, and another instruction will not be accepted
during this time. Any attempt to write data to a register at this time is ignored.
Rasters-rows are driven one at a time according to specific timing to perform liquid crystal display. Bits
NF1 and NF0 indicate display lines, and bits LF3 to LF0 indicate the raster-row in a line. If character
display degenerates when rewriting DDRAM, rewrite only those display lines that are not currently being
read out by the system for display. During segment display, the next state of the last raster-row in the
character display is read out.
Table 9 Display State According to NF1 and NF0
NF1
NF0
Display State
0
0
Displaying the first line
0
1
Displaying the second line
1
0
Displaying the third line
1
1
Displaying the fourth line
Table 10
LF3
0
0
0
0
•
•
•
1
Display State According to LF3 to LF0
LF2
LF1
LF0
Display State
0
0
0
Displaying the first raster-row
0
0
1
Displaying the second raster-row
0
1
0
Displaying the third raster-row
0
1
1
Displaying the fourth raster-row
•
•
•
1
0
0
Displaying the 13th raster-row
R/W RS DB7
DB0
1 0 BF NF1 NF0 0 LF3 LF2 LF1 LF0
Figure 5 Status Register
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