
S1C88409 TECHNICAL MANUAL
EPSON
95
CHAPTER 5: PERIPHERAL CIRCUITS AND OPERATION (LCD Controller)
(3) Hardware auto-transfer mode
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 hardware auto-transfer mode, write
"0" to the S1606 register and write "1" to the
S1570A register.
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 data is written to the display memory,
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 does not need other software
controls because data is automatically trans-
ferred by only writing display data.
This mode can reduce current consumption
better than the continuous data refresh mode.
However, display data is transferred even if
data is written in the scroll area or virtual
screen that are out of the display range. To
avoid such a transfer or to write display data
separately from display update, use the one-
shot transfer with software control.
Figure 5.10.9.7 shows the timing chart in the
hardware auto-transfer mode.
The data transfer status in this mode can be
read from the S1570AS register. The S1570AS
register maintains "1" during data transfer to
indicate that the data transfer circuit is in busy
status. It goes to "0" while the segment drivers
are in self-refresh operation (the data transfer
circuit is in standby status).
LCDEN
FR
YD
LP
1
23
(100)
1
2
3
XSCL
FOSC3
SD0~SD3
Line data
Next line data
Fig. 5.10.9.3 Data transfer in continuous data refresh mode (B&W, 4-bit transfer)
LCDEN
FR
YD
LP
1
23
(100)
1
2
3
XSCL
FOSC3
SD0~SD3
Line data
Next line data
Fig. 5.10.9.4 Data transfer in continuous data refresh mode (gray-scale, 4-bit transfer)