HD66750 Datasheet, PDF (46/96 Pages) Hitachi Semiconductor – 128 x 128-dot Graphics LCD Controller/Driver with Four-grayscale Functions

HD66750/1
4. Read/Write mode 1: AM1Ð0 = 00, LG1Ð0 = 01/10/11
This mode is used when the data is horizontally written at high speed by performing a logical operation
with the original data. It reads the display data (original data), which has already been written in the
graphics RAM (CGRAM), performs a logical operation with the write data sent from the
microcomputer, and rewrites the data to the CGRAM. This mode can read the data during the same bus
cycle as for the write operation since the read operation of the original data does not latch the read data
into the microcomputer and temporarily holds it in the read-data latch. The rotation function (RT2Ð0) or
write-data mask function (WM15Ð0) are also enabled in these operations. After writing, the address
counter (AC) automatically increments by 1 (I/D = 1) or decrements by 1 (I/D = 0), and automatically
jumps to the counter edge one-raster-row below after it has reached the left or right edges of the graphics
RAM.
Operation Examples:
1) I/D = 1, AM1Ð0 = 00, LG1Ð0 = 01 (OR), RT2Ð0 = 000
2) WM15Ð0 = 0000H
3) AC = 000H
WM0
WM15
Write data mask: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Read data (1):
Write data (1):
DB0
DB15
10 0 110 0 10 100 00 1 1
10 1 111 0 00 110 00 0 1
Logical operation
(OR)
10 1 111 0 10 110 00 1 1
Read data (2):
Write data (2):
00 00 11 1 100 00 0 000
11 00 00 1 110 00 1 100
Logical operation
(OR)
11 00 11 1 110 00 1 100
Read data (3):
Write data (3):
00 0 01 110 10 0 00 11 0
01 1 10 100 00 0 11 11 1
Logical operation
(OR)
01 1 11 110 10 0 11 11 1
000H
001H
002H
10 1 111 0 10 11 00 01 1 11 001 1 1 110 00 1 100 01 1 11 11 0 100 11 11 1
Read data (1) + Write data (1) Read data (2) + Write data (2) Read data (3) + Write data (3)
CGRAM
Figure 29 Writing Operation of Read/Write Mode 1
5. Read/Write mode 2: AM1Ð0 = 01, LG1Ð0 = 01/10/11
This mode is used when the data is vertically written at high speed by performing a logical operation
with the original data. It reads the display data (original data), which has already been written in the
graphics RAM (CGRAM), performs a logical operation with the write data sent from the
microcomputer, and rewrites the data to the CGRAM. This mode can read the data during the same bus
cycle as for the write operation since the read operation of the original data does not latch the read data
into the microcomputer and temporarily holds it in the read-data latch. The rotation function (RT2Ð0) or
write-data mask function (WM15Ð0) are also enabled in these operations. After writing, the address
counter (AC) automatically increments by 16, 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 graphics
RAM.
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