HD66766R Datasheet, PDF (52/97 Pages) Hitachi Semiconductor – 132 x 176-dot Graphics LCD Controller/Driver for 65K Colors

HD66766R
Rev. 1.0-1 / September 2002
Write-data Mask Function
The HD66766R has a bit-wise write-data mask function that controls writing the 16-bit 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
DB0
Data written by the
microcomputer
R04 R03 R02 R01 R00 G05 G04 G03 G02 G01 G00 B04 B03 B02 B01 B00
WM15
WMO
Write data
mask
1 1 1 11 0 0 0 00 1 1 1 1 00
GRAM data
DB11
DB0
* * * * * G05 G04 G03 G02 G01 * * * B02 B01 B00
Figure 38 Write-data Mask Function Operation
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