5 POWeR SuPPlY
5-4
Seiko epson Corporation
S1C63003/004/008/016 TeChniCal Manual
(Rev. 1.1)
i/O Memory for Power Supply Circuit
5.5
Table 5.5.1 shows the I/O address and the control bits for power supply control.
5.1 Power supply control bits
Table 5.
Address
Register name R/W Default
Setting/data
Function
FF03H D3
VChlMOD
R/W
0
1 On
0 Off
V
C
regulator heavy load protection mode On/Off
D2
VDhlMOD
R/W
0
1 On
0 Off
V
D
regulator heavy load protection mode On/Off
D1
VCReF (
*
6)
R/W
0
1 V
C2
0 V
C1
V
C
regulator reference voltage selection
D0
lPWR
R/W
0
1 On
0 Off
V
C
regulator On/Off
FF12H D3 FLCKS1
R/W
0
3 –
1 21.3
Frame frequency (Hz) selection
D2 FLCKS0
R/W
0
2 16.0
0 32.0
D1
VCCKS1
R/W
0
3 –
1 2048
V
C
boost frequency (Hz) selection
D0
VCCKS0
R/W
0
2 –
0 Off
*
1 Initial value at initial reset
*
2 Not set in the circuit
*
3 Constantly "0" when being read
*
4 Unused in the S1C63003/004/008
*
5 Unused in the S1C63003/004
*
6 Unused in the S1C63003
lPWR: V
C
regulator On/Off register (FF03h•D0)
Turns the LCD system voltage regulator on and off.
When "1" is written: On
When "0" is written: Off
Reading: Valid
When "1" is written to LPWR, the LCD system voltage regulator goes on and generates the LCD drive voltages.
When "0" is written, all the LCD drive voltages go to V
SS
level. It takes about 100 msec for the LCD drive volt-
ages to stabilize after starting up the LCD system voltage regulator by writing "1" to LPWR. At initial reset, this
register is set to "0."
VCReF: V
C
regulator reference voltage select register (FF03h•D1) – S1C63004/008/016
Selects the reference voltage generated in the LCD system voltage regulator.
When "1" is written: V
C2
When "0" is written: V
C1
Reading: Valid
When "1" is written to VCREF, the LCD system voltage regulator generates the reference voltage V
C2
and gener-
ates two other voltages (V
C1
= V
C2
×
1/2, V
C3
= V
C2
×
3/2) by boosting and reducing V
C2
. When VCREF is "0," the
LCD system voltage regulator generates the reference voltage V
C1
and generates two other voltages (V
C2
= V
C1
×
2, V
C3
= V
C1
×
3) by boosting V
C1
. The reference voltage should be selected from V
C1
and V
C2
with consideration
given to the supply voltage V
DD
and contrast of display. Also refer to the LCD drive voltage - supply voltage
characteristics (in the “Electrical Characteristics - Characteristics Curves” section) and select the appropriate
reference voltage according to the system. At initial reset, this register is set to "0."
In the S1C63003, the reference voltage is selected by mask option.
VDhlMOD: V
D
regulator heavy load protection mode On/Off register (FF03h•D2)
Enables heavy load protection function for the internal operating voltage regulator.
When "1" is written: On
When "0" is written: Off
Reading: Valid
By writing "1" to VDHLMOD, the internal operating voltage regulator enters heavy load protection mode and it
ensures stable V
D1
output. The heavy load protection function is effective when the buzzer/FOUT signal is being
output. However, heavy load protection mode increases current consumption compared with normal operation
mode. Therefore, do not set heavy load protection mode unless it is necessary. At initial reset, this register is set
to "0."