S1C63466 TECHNICAL MANUAL
EPSON
47
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (LCD Driver)
4.7 LCD Driver (COM0–COM16, SEG0–SEG59)
4.7.1 Configuration of LCD driver
The S1C63466 has 17 common terminals (COM0–COM16) and 60 segment terminals (SEG0–SEG59), so
that it can drive a dot matrix type LCD with a maximum of 1,020 (60
× 17) dots.
The driving method is 1/17 duty, 1/16 duty or 1/8 duty dynamic drive with four voltages (1/4 bias),
VC1, VC2, VC4 and VC5 (1/5 bias driving can be set by impressing five voltages from outside).
LCD display ON/OFF can be controlled by the software.
4.7.2 Power supply for LCD driving
VC1–VC5 are driving voltages for the LCD, and for which either the voltages generated by the LCD
system voltage circuit or voltages to be supplied from outside can be used. The built-in LCD system
voltage circuit generates four voltages (1/4 bias) VC1, VC2, VC4 and VC5 except for VC3. These four output
voltages can be supplied to the outside only for driving the externally expanded LCD driver.
When external voltages are supplied, 1/5 bias driving can be made by inputting five voltages to the VC1–
VC5 terminals (including VC3).
Either the internal generated voltages or external voltages used for the LCD drive voltage can be selected
by the mask option.
Turning the LCD system voltage circuit ON or OFF is controlled with the LPWR register. This control is
also necessary when supplying the voltage from outside. When LPWR is set to "1", the LCD system
voltage circuit outputs the LCD drive voltages VC1–VC5 to the LCD driver.
When "internal voltage" is selected by the mask option, the LCD system voltage circuit generates VC1 or
VC2 with the voltage regulator incorporated in itself, and generates three other voltages by boosting or
reducing the voltage VC1 or VC2. Table 4.7.2.1 shows the VC1, VC2, VC4 and VC5 voltage values and boost/
reduce status.
Table 4.7.2.1 LCD drive voltage when generated internally
LCD drive voltage
VC1 (0.975–1.2 V)
VC2 (1.950–2.4 V)
VC4 (2.925–3.6 V)
VC5 (3.900–4.8 V)
VDD = 1.8–6.4 V
VC1 (standard)
2
× VC1
3
× VC1
4
× VC1
VDD = 2.6–6.4 V
1/2
× VC2
VC2 (standard)
3/2
× VC2
2
× VC2
Note: The LCD drive voltage can be adjusted by the software (see Section 4.7.6). Values in the table are
typical values.
Select either VC1 standard or VC2 standard using the VCCHG register.
When "1" is written to the VCCHG register, VC2 standard is selected and when "0" is written, VC1 stan-
dard is selected. At initial reset, VC1 standard (VCCHG = "0") is set.