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The LCD driver control ports are assigned to data control ports 4 and 5; as selected at the select port. These ports are
accessed by using the OUT1 instruction with [CN = 3H, 4H] specified in the operand.
LCD driver segment data
The LCD driver segment data is specified at data ports 4 and 5 (φL13 and φL14). When the segment data port is set
to "0", the LCD display turns off. When the port is set to "1", the LCD display turns on.
LCD OFF bit
The LCD OFF bit controls switching between the LCD output pin and the I/O port. After a reset, the pin that serves
as both an I/O port and LCD driver is in the I/O port state. Set this bit to "0" when using the LCD driver function.
When the LCD driver function is enabled, four of the I/O port pins P10-0 to P10-3 are switched to the COM1 to
COM4 output pins, and four pins P12-0 to P12-3 are switched to the S1 to S4 output pins.
Note:
This bit is set to "1" after a system reset.
DISP OFF bit
The DISP OFF bit allows all the LCD display to turn off without setting segment data. Setting this bit to "1" turns
all the LCD display off. At this time, the segment data is retained. When the DISP OFF bit is set to "0", the previous
display will appear on the LCD as it is.
Note:
Segment data can be rewritten during DISP OFF.
Note:
After the CKSTP instruction is executed, the DISP OFF bit is set to "1". After the CKSTP
instruction is released, set the DISP OFF bit to "0" as required.
Note:
This bit is reset to "0" after system reset.
BIAS bit
The BIAS bit selects the liquid crystal driving method. Set this bit to "0" to select the 1/2 bias method (frame
frequency 62.5 Hz) or set to "1" to select the 1/3 bias method (frame frequency 125 Hz)
In the 1/3 bias mode, the consumption current becomes about 100 µA larger than that in the 1/2
Note:
bias mode.
Note:
This bit is reset to "0" after a system reset.
Segment select port
Each of the 14 pins of I/O ports 13 to 16 can be switched to a segment pin. Set the bit corresponding to each
segment to "1" to use the pin for segment output, or set to "0" to use the pin as an I/O port. The S5 to S8 bits
correspond to pins P13-0 to P13-3 respectively. The S9 to S12 bits correspond to pins P14-0 to P14-3 respectively.
The S13 and S14 bits correspond to pins P15-0 and P15-1 respectively. The S15 to S18 bits correspond to pins P16-0
to P16-3 respectively.
Note:
Segment output and I/O port setting can be made regardless of the LCD off control bit (LCD
OFF). However, the pins that have been set to segment output require setting of the LCD off
control bit to the LCD driver to enable segment output.
Note:
Pins S21 and S22 are also used as high-speed oscillator pins. When they are set to high-speed
oscillator pins, the high-speed oscillator function has priority and this port becomes to "don't
care" state.
Note:
This bit is reset to "0" after a system reset.
93
TC9349AFG
2006-02-24
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