EFM32WG Datasheet, PDF (789/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

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Table 33.6. LCD Principle of Contrast Adjustment for Different Bias Settings.
1/4 bias
Contrast adjustment
relative to V_DD (V_LCD)
(CONCONF = 0)
V_LCD
Rx
V_LC0
R0
V_LC1
R1
V_LC2 V_{LCD_OUT}
R2
V_LC3
R3
V_LC4
Contrast adjustment
relative to GND
(CONCONF = 1)
V_LCD
V_LC0
R0
V_LC1
R1
V_LC2 V_{LCD_OUT}
R2
V_LC3
R3
V_LC4
Rx
No contrast adjustment
(CONLEV = 11111)
V_LCD
V_LC0
R0
V_LC1
R1
V_LC2 V_{LCD_OUT}
R2
V_LC3
R3
V_LC4
1/3 bias
V_LCD
Rx
V_LC0
R0
V_LC1
R1
V_{LCD_OUT}
V_LC2
R2
V_LC3
V_LCD
V_LC0
R0
V_LC1
R1
V_{LCD_OUT}
V_LC2
R2
V_LC3
Rx
V_LCD
V_LC0
R0
V_LC1
R1
V_{LCD_OUT}
V_LC2
R2
V_LC3
1/2 bias
V_LCD
Rx
V_LC0
R0
V_{LC1 VLCD_OUT}
R1
V_LC3
V_LCD
V_LC0
R0
V_LC1 V_{LCD_OUT}
R1
V_LC3
Rx
V_LCD
V_LC0
R0
V_{LC1 VLCD_OUT}
R1
V_LC3
Static
V_LCD
Rx
V_LC0
R0
V_{LCD_OUT}
V_LC3
V_LCD
V_LC0
R0
V_{LCD_OUT}
V_LC3
Rx
V_LCD
V_LC0
V_{LCD_OUT}
V_LC3
R0 = R1 = R2 = R3 in the figure, while Rx is adjusted by changing the CONLEV bits.
33.3.5 V_LCD Selection
By default, the LCD driver runs on main external power (V_LCD = V_DD), see Table 33.7 (p. 790) .
An internal boost circuit can be enabled by setting VBOOSTEN in CMU_LCDCTRL and selecting the
boosted voltage by setting VLCDSEL in LCD_DISPCTRL. This will boosts V_LCD to V_BOOST. V_BOOST can
be selected in the range of 3.0 V – 3.6 V by configuring VBLEV in LCD_DISPCTRL. Note that the boost
circuit is not designed to operate with the selected boost voltage, V_BOOST, smaller than V_DD. The boost
circuit can boost the V_LCD up to 3.6 V when V_DD is as low as 2.0 V.
When using the voltage booster, the LCD_BEXT pin must be connected through a 1 µF capacitor to
VSS, and the LCD_BCAP_P and LCD_BCAP_N pins must be connected to each other through a 22
nF capacitor.
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
789
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