
94
EPSON
S1C88409 TECHNICAL MANUAL
CHAPTER 5: PERIPHERAL CIRCUITS AND OPERATION (LCD Controller)
5.10.9 Data transfer
Transfer data size
The transfer data size can be set to either 8 bits or 4
bits using the BITNO register.
4-bit data transfer only is available for the
S1D16006 and S1D15700 drivers.
(1) 4-bit data transfer (BITNO = "0")
In 4-bit data transfer, data is sent as shown in
Figure 5.10.9.1.
D7 D6 D5 D4 D3 D2 D1 D0
::::::::
xxxxH
:
a
b
c
d
e
f
g
h
xxxx+1H
i
j
k
l
m
n
o
p
Display memory
SD3
:
1
:
a
2
e
SD2
:
b
f
SD1
:
c
g
SD0
:
d
h
3
i
4
m
j
n
k
o
l
p
Data output terminal
LCD panel (B&W)
abcdefghijklmnop...
Fig. 5.10.9.1 4-bit data transfer
(2) 8-bit data transfer (BITNO = "1")
In 8-bit data transfer, data is sent as shown in
Figure 5.10.9.2.
D7 D6 D5 D4 D3 D2 D1 D0
::::::::
xxxxH
:
a
b
c
d
e
f
g
h
xxxx+1H
i
j
k
l
m
n
o
p
Display memory
SD7
:
1
:
a
2
i
SD6
:
b
j
SD5
:
c
k
SD4
:
d
l
SD3
:
e
m
SD2
:
f
n
SD1
:
g
o
SD0
:
h
p
Data output terminal
LCD panel (B&W)
abcdefghijklmnop...
Fig. 5.10.9.2 8-bit data transfer
Data transfer method
The LCD controller has three data transfer modes
for sending data to the segment drivers.
(1) Continuous data refresh mode
This mode is available for both the S1D16006
and S1D15700 segment drivers. The S1D16006
and the gray-scale display can be controlled
only in this mode.
The continuous data refresh mode is set by
writing "1" to the S1606 register. It is also set at
initial reset.
In this mode, the display memory data is
continuously sent to the segment driver in
every frames while the LCDEN register is "1".
Figures 5.10.9.3 to 5.10.9.5 show the timing
charts in the continuous data refresh mode.
(2) One-shot transfer mode (software control)
This mode is available only for the S1D15700
segment driver and only in the B&W mode.
The S1D16006 and the gray-scale display
cannot use this mode.
To set the one-shot transfer mode, write "0" to
the S1606 and S1570A registers.
When "1" is written to the LCDEN register, the
LCD controller outputs only the FR, LP and YD
signals for a self-refresh of the S1D15700.
When updating the display, rewrite the display
memory then write "1" to the S1570O register.
The LCD controller outputs one-frame data in
the frame cycle immediately after the writing.
After that, the LCD controller outputs the FR,
LP and YD signals only.
This mode is best to reduce current consump-
tion in the three transfer mode because data is
transferred only when it is necessary.
Figure 5.10.9.6 shows the timing chart in the
one-shot transfer mode.
The S1570O register, which is used for a trigger
of the one-shot transfer, can be read as a status.
After "1" is written to the S1570O register, the
register maintains "1" until the data transfer
has completed to indicate that the data transfer
circuit is in busy status. A new data transfer
cannot be started during this period (writing
"1" to the S1570O register is ignored).
Further this mode can generate an interrupt at
the end of a data transfer (see the next section).
When updating the display, check to see if the
data transfer is possible using these functions.