HD66773R Datasheet, PDF (82/133 Pages) Renesas Technology Corp – 262,144-color, 132 x 176-dot Graphics Controller Driver for TFT LCD panels

HD66773R
8. Read/Write mode 4: AM = 1, LG2–0 = 100/101
This mode is used when data are vertically written in high-speed with performing compare operation on the
GRAM data (base data) and the value set in the compare register (CP15-0). The compare operation is
performed on the GRAM read-out data and the value set in the compare register by word. When the result
of the comparison satisfies a condition, the data sent from the microcomputer are written to GRAM. In the
read operation, the GRAM data is not read out to the microcomputer but retained temporarily in the read-
data latch of the HD66773R. Accordingly, the read operation can be performed using the same pulse width
with the write-access pulse (68-system: ENABLE “High” level width, 80-system: ENABLE “Low” level
width), but requires the same bus cycle time as the normal read operation. In this operation, the write-data
mask function (WM15–0) is available. After writing, the address counter (AC) automatically increments
by 256, and automatically jumps to the counter either at the top of the next right row (ID = 1) or the next
left row (I/D = 0) according to the setting in the I/D bit, when the address reaches the bottom of GRAM.
Operation Examples:
1) I / D = "1", AM = "1", LG2-0 = "101" (unmatched write)
2) CP15-0 = "2860"H
2) WM15-0 = "0000"H
3) AC = "0000"H
Write-data mask:
Compare register:
WM15
00 0 00 00 0
CP15
00 1 01 00 0
WM0
0 00 00 00 0
CP0
Compare
operation
0 11 0 0000
Read data (1):
Write data (1):
Read data (2):
Write data (2):
Unmatched
DB17
DB10 DB8
DB1
10 0 11 00 1 0 10 11 11 1 ^C
Matched
10 1 11 10 0
0 11 00 00 0
Compare
operation
00 1 01 00 0 0 11 0 00 00
C
11 00 00 11 10 000 00 0
Conditional
replacement
R
10 1 11 10 00 11 00 00 0
Conditional
replacement
R
00 1 01 00 00 11 0 00 00
"0000"H
"0100"H
"0000"H
10 1 11 10 00 11 0 00 00
00 1 01 00 00 11 0 00 00
"0001"H
Write data (1)
Write data (2)
"AF00"H
GRAM
Note 1) The data in the bit with "*" are not overwritten.
Note 2) When data are written to the address "AF00"H, the Address Counter
(AC) jumps to "0001"H.
Rev.1.10, Jun.21.2003, page 82 of 133