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CHAPTER 17 LCD CONTROLLER/DRIVER
User
’
s Manual U14701EJ3V0UD
Cautions 1. Set the LCDON, SCOC, and VLCON bits in the following sequence:
To display LCD while LCD booster circuit stops
(1) Set VLCON to 1. All the segment and common pins are in the GND output mode
(SCOC = 0).
↓
(2) Set VLCON to 1 and wait 500 ms or longer with software.
↓
(3) Set SCOC to 1. All the segment and common pins output an unselect waveform and
are in unselect display mode.
↓
(4) Set LCDON to 1. The value of the display RAM is reflected on the segment output
waveform, and all segment and common pins are in select display mode.
To stop LCD booster circuit while LCD displays
(1) Clear LCDON to 0. All the segment and common pins are in unselect display mode.
↓
(2) Clear SCOC to 0. All the segment and common pins are in GND output mode.
↓
(3) Clear VLCON to 0. The LCD booster circuit stops.
2. The blinking cycle is generated using the interval time (0.5 s at 32.768 kHz) of the watch
timer. When the blinking function is not used (BLON = 0), the LCD lights or extinguishes
depending on the setting of the display RAM, as shown in Figure 17-3. To use the blinking
function (BLON = 1), the LCD lights or extinguishes depending on the status of the internal
blinking clock signal (set value of BLSEL), i.e., it lights if the internal blinking clock signal
is “1” and extinguishes if the signal is “0”.
Figure 17-3. Blinking Function
3. When using the blinking function, the LCD does not blink even if the data is rewritten while
the LCD is in the extinguishing cycle (0.5 s or 1.0 s), unless the LCD is in the lighting cycle.
Extin-
guishes
Lights
Display RAM
0.5 s
0.5 s
0.5 s
0.5 s
Watch timer
Interrupt
internal blinking
Clock signal
display RAM
BLON
Display status
Internal blinking clock signal
Extinguishes
Lights