HD66787 Datasheet, PDF (112/159 Pages) Renesas Technology Corp – 528-channel, One-chip Driver with 262,144-color Display RAM and Power Supply Circuit for Low-temperature Poli-Si TFT (LTPS-TFT) Panels with Incorporat

HD66787
Preliminary
Write-data Mask Function
The HD66787 expands the 16-bit data sent from the microcomputer into the 18-bit data. In the18-bit
interface mode, data are not expanded. The write data mask function of the HD66787 controls the write
operation of the 18-bit data from the microcomputer to GRAM by bit. The write data mask function write
data in the bits whose corresponding bits in the write data mask resister (WM17–0) are assigned with “0”
and does not write data in the bits whose corresponding bits in the write data mask register (WM17–0) are
assigned with “1”, and the corresponding data in GRAM are not overwritten but retained. This function is
useful when only one-pixel data are rewritten or a particular color in the display is selectively changed.
DB17
DB0
Data from R05 R04 R03 R02 R01 R00 G05 G04 G03 G02 G02 G01 G00 B05 B04 B03 B02 B01 B00
the microcomputer
WM17
WM0
Write data mask _{1 1 1 1 1 1 0 0 0 0 0 0 0 1 1 1 1 0 0}
17
0
GRAM data _{* * * * * * * G05 G04 G03 G02 G02 G01 G00 * * * B01 B00}
Note : Data are expanded into 18 bits in the 8/16-bit system interface and the 16 RGB interface modes.
Write data mask function
Graphics Operation Processing Examples
1. Write mode 1: AM = 0, LG2–0 = 000
This mode is used when data are horizontally written in high speed mode. It is also used to initialize the
graphics RAM (GRAM) or to draw a line horizontally. The write-data mask function (WM17–0) is also
available in these operations. After writing, the address counter (AC) automatically increments by 1 (I/D =
1) or decrements by 1 (I/D = 0), and jumps to the counter at the opposing edge of the next one-raster-row
below after when the counter reaches either left or right edge of GRAM.
Operation example
1) I/D = "1", AM = "0", LG2-0 = "000"
2) WM17-0 = "00FFF"H
3) AC = "0000"H
WM17
WM0
Write-data mask: 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1
Write-data (1)
DB17
DB0
100111111100101000
Write-data (2) 1 1 0 0 0 1 0 0 0 0 0 1 1 0 0 0 0 0
*Write-mask <G>, <B> planes.
Data are expanded into 18 bits in 8/16-bit system
interface, and 16-bit RGB interface modes.
“0000”H
“ 0001” H
100111* * * * * * * * * * * * 110001* * * * * * * * * * * *
Write data (1)
Write data (2)
“ 0002”H
GRAM
Note : The bits in the GRAM with “"*"
are not overwritten.
Write Mode 1
Rev.0.22, May.23.2003, page 112 of 159