HD66760 Datasheet, PDF (53/105 Pages) Hitachi Semiconductor – 104 X 80-dot Graphics LCD Controller/Driver for 256 Colors

HD66760
Logical/Compare Operation Function
The HD66760 performs a logical operation or conditional replacement between the two-byte write data sent
from the microcomputer and the read data from the GRAM. The logical operation function has four types:
replacement, OR, AND, and EOR. The conditional replacement performs a compare operation for the set
value of the compare register (CP7-0) and the read data value from the GRAM, and rewrites only the pixel
data in the GRAM that satisfies the conditions (in a byte unit). This function can be used when a particular
color is selectively rewritten. The swap function or write-data mask function can be effectively used.
Table 32 Logical/Compare Operation
Bit Setting
LG2 LG1 LG0 Description of Logical/Compare Operation Function
0
0
0
Writes the data written from the microcomputer directly to the GRAM. Only write
processing is performed since the data in the read-data latch is not used.
0
0
1
ORs the data in the read-data latch and the data written by the microcomputer.
Writes the result to GRAM. Read, modify, or write processing is performed.
0
1
0
ANDs the data in the read-data latch and the data written by the microcomputer.
Writes the result to GRAM.
0
1
1
EORs the data in the read-data latch and the data written by the microcomputer.
Writes the result to GRAM.
1
0
0
Compares the data in the read-data latch and the set value of the compare register
(CP7–0). When the read data matches CP7–0, the data from the microcomputer is
written to the GRAM. Only the particular color specified in the compare register
can be rewritten. Read, modify, or write processing is performed.
1
0
1
Compares the data in the read-data latch and the set value of the compare register
(CP7–0). When the read data does not match CP7-0, the data from the
microcomputer is written to the GRAM. Colors other than the particular one
specified in the compare register can be rewritten. Read, modify, or write
processing is performed.
1
1
0
Compares the data written to the GRAM by the microcomputer and the set value of
the compare register (CP7–0). When the write data matches CP7-0, the data from
the microcomputer is written to the GRAM. Only write processing is performed.
1
1
1
Compares the data written to the GRAM by the microcomputer and the set value of
the compare register (CP7–0). When the write data does not match CP7-0, the
data from the microcomputer is written to the GRAM. Only write processing is
performed.