M38203M4 Datasheet, PDF (258/344 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.7 LCD drive control circuit
2.7.6 Notes on use
(1) For transition from the high-speed or the middle-speed mode to the low-power operation of the low-
speed mode:
ΠSelect oscillation at 32 kHz (CM4 = 1)
 Count source for LCDCK; select f(XCIN)/32 (LM7 = 0)
Ž Internal system clock; select XCIN–XCOUT (CM7 = 1)
 Stop main clock XIN–XOUT (CM5 = 1)
In the above order, execute transition. Execute the setting  after the oscillation at 32 kHz
(setting Œ) becomes completely stable.
(2) If the STP instruction is executed while the LCD is turned on by setting bit 3 of the LCD mode register
to “1,” a DC voltage is applied to the LCD. For this reason, do not execute the STP instruction while
the LCD is lighting.
(3) When the LCD is not used, open the segment and the common pins.
Connect VL1–VL3 to VSS.
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3820 GROUP USER’S MANUAL