HD66760 Datasheet, PDF (52/105 Pages) Hitachi Semiconductor – 104 X 80-dot Graphics LCD Controller/Driver for 256 Colors

HD66760
Write-data Mask Function
The HD66760 has a bit-wise write-data mask function that controls writing the two-byte data from the
microcomputer to the GRAM. Bits that are 0 in the write-data mask register (WM15-0) cause the
corresponding DB bit to be written to the GRAM. Bits that are 1 prevent writing to the corresponding GRAM
bit to the GRAM; the data in the GRAM is retained. This function can be used when only one-pixel data is
rewritten or the particular display color is selectively rewritten.
DB15
DB8
Data written by
R02 R01 R00 G02 G01 G00 B02 B01
the microcomputer
Upper byte
DB7
R12 R11
DB0
R10 G12 G11 G10 B12 B11
Lower byte
i) SWP = "0":
DB15
DB8 DB7
DB0
R02 R01 R00 G02 G01 G00 B02 B01 R12 R11 R10 G12 G11 G10 B12 B11
Upper byte
Lower byte
ii) SWP = "1":
DB7
DB0 DB15
DB8
R12 R11 R10 G12 G11 G10 B12 B11 R02 R01 R00 G02 G01 G00 B02 B01
Lower byte
Upper byte
WM15
WM8 WM7
WM0
Write-data mask _{1 1 1 1 1 1 1 1 0 0 0 1 1 1 0 0}
i) GRAM data
(SWP = "0"):
DB15
**
****
Upper byte
DB8 DB7
DB0
* * ^{R12 R11 R10} * * * ^{B12 B11}
Lower byte
ii) GRAM data
(SWP = "1"):
DB7
**
****
Lower byte
DB0 DB15
DB8
* * ^{R02 R01 R00} * * * ^{B02 B01}
Upper byte
Figure 33 Example of Write-data Mask Function Operation