HD66773R Datasheet, PDF (80/133 Pages) Renesas Technology Corp – 262,144-color, 132 x 176-dot Graphics Controller Driver for TFT LCD panels

HD66773R
6. Read/Write mode 2: AM = 1, LG2–0 = 110/111
This mode is used when data are vertically written in high-speed with performing logical operation on the
GRAM data (base data) and data from the microcomputer. The logical operation is performed on the
GRAM read-out data and the data sent from the microcomputer, and the result of the logical operation is
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 = "001"(OR)
2) WM15-0 = "FFE0"H
3) AC = "0000"H
Write-data mask:
WM15
11 1 11 11 1
WM0
1 11 00 00 0
Read data (1):
Write data (1):
DB17
DB10 DB8
DB1
1 00 01 00 1 0 10 11 11 1
1 01 11 10 0 0 11 00 00 0
Logical
operation(OR)
10 11 1 1 0 1 0 1 1 11111
Read data (2):
Write data (2):
0 0 001 11 1 0 00 00 00 0
1 1 0 0 0 0 1 1 10 0 1 1 1 1 1
Logical
Operation(OR)
1 10 0 1 1 1 1 1 0 0 1111 1
"0000"H
"0100"H
"0000"H
* * * * * * * * * * * 111 1 1
* * * * * * * * * * * 00 00 0
"0001"H
Read data (1) + Write data (1)
Read data (2) + 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 80 of 133