Specifications

S1C6P466 TECHNICAL MANUAL EPSON 43
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (LCD Driver)
4.7 LCD Driver (COM0–COM16, SEG0–SEG59)
4.7.1 Configuration of LCD driver
The S1C6P466 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),
V
C1, VC2, VC4 and VC5.
LCD display can be controlled by the software.
4.7.2 Power supply for LCD driving
VC1–VC5 are the LCD drive voltages generated by the LCD system voltage circuit.
The built-in LCD system voltage circuit generates four voltages (1/4 bias) V
C1, VC2, VC4 and VC5 except
for V
C3. These four output voltages can be supplied to the outside only for driving the externally ex-
panded LCD driver.
Turning the LCD system voltage circuit ON or OFF is controlled with the LPWR register. When LPWR is
set to "1", the LCD system voltage circuit outputs the LCD drive voltages V
C1–VC5 to the LCD driver.
The LCD system voltage circuit generates V
C1 or VC2 with the voltage regulator incorporated in itself,
and generates three other voltages by boosting or reducing the voltage V
C1 or VC2. Table 4.7.2.1 shows the
V
C1, VC2, VC4 and VC5 voltage values and boost/reduce status.
Table 4.7.2.1 LCD drive voltage when generated internally
LCD drive voltage
V
C1 (0.975–1.2 V)
V C2 (1.950–2.4 V)
V
C4 (2.925–3.6 V)
V C5 (3.900–4.8 V)
V
C1 standard
V
C1 (regulated)
2 × V C1
3 × V C1
4 × V C1
V C2 standard
1/2 × V
C2
V C2 (regulated)
3/2 × V
C2
2 × V C2
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, V
C2 standard is selected and when "0" is written, VC1 stan-
dard is selected. At initial reset, V
C1 standard (VCCHG = "0") is set.
In the S1C6P466, either can be selected regardless of the supply voltage level since the minimum operat-
ing voltage is 2.7 V.
The V
C2 standard improves the display quality and reduces current consumption, note, however, the VC1
standard must be set in the mask ROM model (S1C63454/63458/63466) if the power supply voltage VDD
is 2.6 V or less. Pay attention when using the S1C6P466 as a development tool for these models.
4.7.3 Mask option
The S1C6P466 generates the LCD drive voltage using the internal power supply circuit and does not
allow use of an external power source.