hd66765 Renesas Electronics Corporation., hd66765 Datasheet - Page 46

• Manufacturer Part Number: hd66765
• Description: 396-channel Segment Driver With Internal Ram For 4096-color Displays - Hitachi Semiconductor
• Manufacturer: Renesas Electronics Corporation.

HD66765
Graphics Operation Function
The HD66765 can greatly reduce the load of the microcomputer graphics software processing through the
16-bit bus architecture and internal graphics-bit operation function. This function supports the following:
Even if the display size is large, the display data in the graphics RAM (GRAM) can be quickly rewritten.
The graphics bit operation can be controlled by combining the entry mode register, the bit set value of the
RAM-write-data mask register, and the read/write from the microcomputer.
Table 23
Operation Mode
Write mode 1
Write mode 2
Write mode 3
Write mode 4
Read/write mode 1
Read/write mode 2
Read/write mode 3
Read/write mode 4
1. A write data mask function that selectively rewrites some of the bits in the 12-bit write data.
2. A logical operation write function that writes the data sent from the microcomputer and the
3. A conditional write function that compares the original RAM data or write data and the compare-
original RAM data by a logical operation.
bit data and writes the data sent from the microcomputer only when the conditions match.
Graphics Operation
Bit Setting
I/D
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
AM
0
1
0
1
0
1
0
1
LG2–0
000
000
110 111
110 111
001 010
011
001 010
011
100 101
100 101
Operation and Usage
Horizontal data replacement, horizontal-border
drawing
Vertical data replacement, vertical-border drawing
Conditional horizontal data replacement, horizontal-
border drawing
Conditional vertical data replacement, vertical-border
drawing
Horizontal data write with logical operation,
horizontal-border drawing
Vertical data write with logical operation, vertical-
border drawing
Conditional horizontal data replacement, horizontal-
border drawing
Conditional vertical data replacement, vertical-border
drawing
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