Sharp ER-A750 Service Manual page 51

2-9. SED1351FOA/LB
The SED1351FOA/LB is a display controller that is used for the
high-duty dot matrix type LCD for graphic display.
This unit can interface with an 8-bit or 16-bit MPU with the READY
(WAIT) input terminal. Access to the VRAM is performed by the cycle
steal method so that distortion of the screen is minimal. Also, the
unit incorporates all the addresses and the data control circuits
necessary for cycle steal, requiring no external circuit. The chip
select output terminal for VRAM allows direct connection of eight
64K SRAMs or two 256K SRAMs without having to use any external
decoder circuit.
The VRAM is mapped on the MPU's memory space to make it
possible to address all the display data directly from the MPU, thus
providing efficient processing of display data including those of
pictures.
The SED1351F has two display modes: the conventional ON/OFF
OA
binary display mode and the gradation display mode including
ON/OFF and pseudo intermediate double tone. In the binary display
mode, the maximum number of display dots is 524288 dpi and in
the gradation display mode, it is 262144 dpi, when all the 64KB of
memory of the VRAM.
1) FEATURES:
•
The unit can be controlled with an 8-bit or 16-bit MPU (Intel MPU).
•
Can be interfaced with the MPU by the READY (WAIT) signal.
•
Access from MPU to VRAM is performed through the cycle steal
method No effect on the screen.
•
VRAM
Mapping .............MPU memory space
Capacity..............64 Kbytes (2
•
LCD display mode
Binary display mode (ON/OFF)
Graduation display mode (ON/OFF and pseudo intermediate dou-
ble tone)
•
LCD panel
Single screen drive panel (Transfer by 4 bits or 8 bits
Double screen drive panel (4 bits
•
Maximum number of characters in horizonal direction
(256 characters)
2048 dots (binary display mode)
1024 dots (graduation display mode)
•
Maximum number of vertical lines
1024 lines (single screen drive)
2048 lines (double screen drive)
•
Divided screen/OR function (Either function is available when sin-
gle screen drive is set)
Divided screen.... The screen can be divided into two upper and
lower sections.
OR function ........Two different data can ORed.
•
Virtual display can be set.
•
Smooth scroll in vertical direction.
•
Built-in chip select output for VRAM.
•
CMOS operation
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