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5 PERIPHERAL CIRCUITS AND THEIR OPERATION (LCD Driver)
5.11 LCD Driver
5.11.1 Configuration of LCD driver
The S1C88650 has a built-in dot matrix LCD driver
that can drive an LCD panel with a maximum of
4,032 dots (126 segments 32 commons).
Figure 5.11.1.1 shows the configuration of the LCD
driver and the drive power supply.
OSC1 oscillation
V
D2
CF
CG
VDSEL
V
C1
V
C2
V
C3
V
C4
V
C5
CA
CB
CC
CD
CE
V
SS
108
Programmable timer 5
underflow signal
f
OSC1
circuit
Power voltage
booster
V
V
D2
DD
LCD system
voltage regulator
Fig. 5.11.1.1 Configuration of LCD driver and drive power supply
5.11.2 LCD power supply
The S1C88650 generates the LCD drive voltages
V
to V
using the internal power supply circuit.
C1
C5
It is not necessary to apply an external voltage.
Note that the internally generated voltage cannot
be used for driving external loads.
The LCD system voltage regulator can be driven
with V
or V
DD
voltage level. Use the LCD system voltage regulator
power select register VDSEL for this switching.
When VDSEL is set to "0", V
when VDSEL is set to "1", V
voltage is generated by approximately doubling the
V
voltage in the power voltage booster circuit.
DD
When using V
booster circuit ON/OFF control register DBON to
turn the power voltage booster circuit on. This must
be done before the power source of the LCD system
voltage regulator can be switched to V
Clock
control
circuit
Divider
DBON
LCD contrast
adjustment circuit
V
V
C1–
C5
LCD driver
Display memory
EPSON
depending on the power supply
D2
is selected and
DD
is selected. The V
D2
, write "1" to the power voltage
D2
FRMCS
LC3
LC2
LC1
LC0
LCDC1
LCDC0
DTFNT
LDUTY1
LDUTY0
SEGREV
COM0–COM31
SEG0–SEG125
DSPAR
S1C88650 TECHNICAL MANUAL
D2
.
D2
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