S1C6P466 TECHNICAL MANUAL
EPSON
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CHAPTER 2: POWER SUPPLY AND INITIAL RESET
2.1.1 Voltage <VD1> for oscillation circuit
VD1 is the operating voltage for the oscillation circuit, and is generated by the oscillation system voltage
regulator for stabilizing the oscillation.
In the S1C63454/63458/63466, it is necessary to switch the VD1 voltage level according to the oscillation
circuit and operating frequency by controlling the voltage regulator. In the S1C6P466, the VD1 voltage
level is fixed, so software control for switching the VD1 level does not affect the actual output voltage.
Refer to Chapter 6, "Differences from Mask ROM Models", for details.
2.1.2 Voltage <VC1–VC5> 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) VC1, VC2, VC4 and VC5 (excluding VC3). These
four output voltages can only be supplied to the externally expanded LCD driver.
The LCD system voltage circuit generates VC1 or VC2 with the voltage regulator built-in, and generates
three other voltages by boosting or reducing the voltage of VC1 or VC2. Table 2.1.2.1 shows the VC1, VC2,
VC4 and VC5 voltage values and boost/reduce status.
Table 2.1.2.1 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)
VC1 standard
VC1 (regulated)
2
× VC1
3
× VC1
4
× VC1
VC2 standard
1/2
× VC2
VC2 (regulated)
3/2
× VC2
2
× VC2
Note: The LCD drive voltage can be adjusted by the software (see Section 4.7.6). Values in the above
table are typical values.
Either the VC1 or VC2 used for the standard is selected according to the supply voltage by the software.
In the S1C6P466, either can be selected regardless of the supply voltage level since the minimum operat-
ing voltage is 2.7 V.
The VC2 standard improves the display quality and reduces current consumption, note, however, the VC1
standard must be set in the mask ROM model if the power supply voltage VDD is 2.6 V or less.
Refer to Section 4.7, "LCD Driver", for control of the LCD drive voltage.