
100
EPSON
S1C88409 TECHNICAL MANUAL
CHAPTER 5: PERIPHERAL CIRCUITS AND OPERATION (LCD Controller)
DISP: Display ON/OFF control register
(00FF60HD7)
Turns the display on and off.
When "1" is written: ON
When "0" is written: OFF
Reading: Valid
When "1" is written to the DISP register, the DOFF
terminal goes low and when "0" is written, the
DOFF terminal goes high.
This signal controls the external driver to turn the
display on and off.
At initial reset, the DISP register is set to "0" (OFF).
REV: Normal/reverse display control register
(00FF60HD6)
Controls reverse display.
When "1" is written: Reverse display
When "0" is written: Normal display
Reading: Valid
When "1" is written to the REV register, the display
reverses and when "0" is written, it returns to the
normal. When using an LCD panel with a back
light, the setting reverses.
At initial reset, the REV register is set to "0"
(normal).
POINT5, CKCN0–CKCN2: Scanning line
frequency selection register (00FF60HD2–D5)
Selects a scanning line frequency from 16 types as
shown in Table 5.10.11.2.
Table 5.10.11.2 Selection of scanning line frequency
CKCN2
0
1
CKCN1
0
1
0
1
CKCN0
0
1
0
1
0
1
0
1
POINT5
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Frequency
fOSC1
fOSC1/1.5
fOSC1/2
fOSC1/2.5
fOSC1/3
fOSC1/3.5
fOSC1/4
fOSC1/4.5
fOSC1/5
fOSC1/5.5
fOSC1/6
fOSC1/6.5
fOSC1/7
fOSC1/7.5
fOSC1/8
fOSC1/8.5
The frame frequency is set as "scanning frequency
/ (SLT+1)".
At initial reset, these registers are set to "0" (fOSC1).
GRAY: Gray-scale/B&W mode selection register
(00FF60HD1)
Selects the gray-scale mode or B&W mode.
When "1" is written: Gray-scale mode
When "0" is written: B&W mode
Reading: Valid
When "1" is written to the GRAY register, the gray-
scale mode is set and it displays a dot with 2 bits
of the display memory.
When "0" is written, the B&W mode is set and each
bit of the display memory corresponds to a dot on
the LCD panel one to one.
At initial reset, the GRAY register is set to "0"
(B&W mode).
BITNO: 8-bit/4-bit transfer selection register
(00FF60HD0)
Set the transfer data size.
When "1" is written: 8 bits
When "0" is written: 4 bits
Reading: Valid
BITNO sets the size of data to be transferred to the
segment drivers. When "1" is written to the BITNO
register, 8-bit transfer is set and when "0" is
written, 4-bit transfer is set. The 4-bit transfer uses
the data output terminals SD0 to SD3 only.
When using S1606 or S1570 as the segment driver,
fix this register at "0".
When the gray-scale mode is selected, 4-bit
transfer only is available regardless of the BITNO
register setting.
At initial reset, the BITNO register is set to "0" (4
bits).
LCDEN: LCD power control register
(00FF61HD3)
Controls the power of the LCD controller.
When "1" is written: ON
When "0" is written: OFF
Reading: Valid
When "1" is written to the LCDEN register, the
power of the LCD controller turns on and when "0"
is written, it turns off.
The LCDEN terminal goes high while the LCDEN
register is "1" and goes low while the register is "0".
Use this signal for controlling the power of the
LCD panel so that the LCD panel does not turn on
while the LCDEN is "0".
At initial reset, the LCDEN register is set to "0"
(OFF).