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Table 14.4.4.1 Selecting Reference Voltage for Boosting Voltage According to Power Supply Voltage V
LCD8PWR.VCSEL bit
By setting the LCD8PWR.HVLD bit to 1, the LCD voltage regulator enters heavy load protection mode and en-
sures stable V
to V
outputs. Heavy load protection mode should be set when the display has inconsistencies in
C1
C3
density. Current consumption increases in heavy load protection mode, therefore do not set heavy load protection
mode if unnecessary.
14.4.5 LCD Voltage Booster Setting
Set the booster clock frequency used in the LCD voltage booster using the LCD8TIM.BSTC[1:0] bits. Set it to the
frequency that provides the best V
14.4.6 LCD Contrast Adjustment
The LCD panel contrast can be adjusted within 16 levels using the LCD8PWR.LC[3:0] bits. This function is real-
ized by controlling the voltage output from the LCD voltage regulator. Therefore, the LCD8PWR.LC[3:0] bits can-
not be used for contrast adjustment in external voltage application modes 1 and 2.
14.5 Operations
14.5.1 Initialization
The LCD8A should be initialized with the procedure shown below.
1. Assign the LCD8A output function to the ports. (Refer to the "I/O Ports" chapter.)
2. Configure the LCD8CLK.CLKSRC[1:0] and LCD8CLK.CLKDIV[2:0] bits. (Configure operating clock)
3. Write 1 to the LCD8CTL.MODEN bit.
4. Configure the following LCD8TIM register bits:
- LCD8TIM.LDUTY[2:0] bits
- LCD8TIM.FRMCNT[3:0] bits
- LCD8TIM.NLINE[2:0] bits
- LCD8TIM.BSTC[1:0] bits
5. Configure the following LCD8PWR register bits:
- LCD8PWR.VCEN bit
- LCD8PWR.VCSEL bit
- LCD8PWR.BSTEN bit
- LCD8PWR.LC[3:0] bits
6. Configure the following LCD8DSP register bits:
- LCD8DSP.DSPAR bit
- LCD8DSP.COMREV bit
- LCD8DSP.SEGREV bit
7. Write display data to the display data RAM.
8. Set the following bits when using the interrupt:
- Write 1 to the LCD8INTF.FRMIF bit.
- Set the LCD8INTE.FRMIE bit to 1.
S1C17M01 TECHNICAL MANUAL
(Rev. 1.2)
Power supply voltage V
0
1.8 to 5.5 V
1
2.5 to 5.5 V
–V
output stability after being evaluated using the actual circuit board.
C1
C3
(Enable LCD8A operating clock)
(Set drive duty)
(Set frame frequency)
(Set n-line inverse AC drive)
(Set booster clock frequency)
(Enable LCD voltage regulator)
(Set reference voltage for boosting)
(Enable LCD voltage booster)
(Set LCD contrast initial value)
(Select display area)
(Select COM pin assignment direction)
(Select SEG pin assignment direction)
(Clear interrupt flag)
(Enable LCD8A interrupt)
Seiko Epson Corporation
14 LCD DRIVER (LCD8A)
Reference voltage for
DD
boosting voltage
V
C1
V
C2
DD
14-5
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