HD66730 Datasheet, PDF (82/131 Pages) Hitachi Semiconductor – Dot-Matrix Liquid Crystal Display Controller/Driver Supporting Japanese Kanji, Korean Font Display

HD66730/HD66731
Initial Setting of Pin Functions
1. Bus/serial interface
The input level of pin IM selects the 8-bit bus or serial interface. For an 8-bit bus interface, data is
written into the index register or read from the status register according to the level of pin R/W. Note
that pin RS must be held low during this time. For serial interface, data is written into the index register
according to bit R/W. Note that bit RS must be 0 during this time. During reset, only the index register
and status register can be set and RAM cannot be accessed.
2. LCD driver output
Since segment drivers (pins SEG1 to SEG71/119) are in a display-off state during reset, they output
non-selective levels (V2/V3 level) during reset. At this time, a 4-line 6-character display alternates its
current. Common drivers (pins COM1 to COM24/53 and COMS) output non-selective levels (V1/V4
level) during reset, and alternate its current for a 4-line 6-character display.
Note: Pins COM25/COMD of HD66730 are grounded (0V) during reset. When pin COM25 is used
without expanding drivers to the common side, display may be performed using the liquid crystal
drive voltage. In this case, adjust the liquid crystal voltage during reset.
3. Extension driver interface output (HD66730)
Since bits EXT2/1 are 11 during reset, extension is performed to both segment side and common side.
Pin CL2 outputs the oscillation (operation) frequency clock. Pins CL1 and M output signals in a cycle
corresponding to a 4-line 6-character display size. In addition, pins SEGD and COM25/COMD output
low (ground level) since the display is turned off.
4. Booster output
The operation of the internal booster stops because bit BST becomes 0 during reset.
Note: The potential of pins V5OUT2 and V5OUT3 increases by about +0.7 V with respect to GND level
when the booster stops. When using external polarized capacitors, make sure that no reverse bias
occurs.
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