HD66760 Datasheet, PDF (57/105 Pages) Hitachi Semiconductor – 104 X 80-dot Graphics LCD Controller/Driver for 256 Colors

HD66760
4. Write mode 4: AM = 1, LG2–0 = 110/111
This mode is used when a vertical comparison is performed between the write data and the set value of the
compare register (CP7–0) to write the data. When the result by the comparison in a byte unit satisfies the
condition, the write data sent from the microcomputer is written to the GRAM. In this operation, the swap
function (SWP) and write-data mask function (WM15–0) are also enabled. After writing, the address
counter (AC) automatically increments by 256, and automatically jumps to the upper-right edge (I/D = 1)
or upper-left edge (I/D = 0) following the I/D bit after it has reached the lower edge of the GRAM.
Operation Examples:
1) I/D = "1", AM = "1", LG2-0 = "111" (unmatched write), SWP = "0"
2) CP7–0 = "53H"
3) WM15–0 = "0000"H
4) AC = "000"H
WM15
WM0
Write-data mask: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
CP7
CP0
Compare register: 0 ₁ 0 ₁ 0 0 _{1 1}
Compare operation
DB15 ^(Unmatched)
DB0
Write data (1): _{1 0 0 1 1 0 0 1 0 1 0 1 0 0 1 1 C}
R
Compare
operation
(Unmatched) (Unmatched)
Write data (2): ^{0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0}
C
R
Compare
(Unmatched) _operation
Write data (3): ^{0 1 0 1 0 0 1 1 1 0 0 0 0 1 1 0}
CR
Conditional replacement
10 0 11 00 1 * * * * * * * *
Conditional replacement
0 0 0 0 1 1 1 1 0 0 0 0 0 00 0
Conditional replacement
* * * * * * * * 10 00 01 1 0
"0000"H
"0001"H
"0000"H 1 0 0 1 1 0 0 1 * * * * * * * * ^{Write data (1)}
"0080"H 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 ^{Write data (2)}
"0100"H * * * * * * * * 1 0 0 0 0 1 1 0 ^{Write data (3)}
"4F00"H
Notes: 1. The bits in the GRAM indicated by '*' are not changed.
2. After writing to address 4F00H, the AC jumps to 0001H.
GRAM
Figure 37 Writing Operation of Write Mode 4