Datasheet

 2008-2011 Microchip Technology Inc. DS41364E-page 335
PIC16(L)F1934/6/7
27.3 LCD Bias Voltage Generation
The LCD module can be configured for one of three
bias types:
• Static Bias (2 voltage levels: V
SS and VLCD)
• 1/2 Bias (3 voltage levels: VSS, 1/2 VLCD and
V
LCD)
• 1/3 Bias (4 voltage levels: VSS, 1/3 VLCD,
2/3 V
LCD and VLCD)
TABLE 27-2: LCD BIAS VOLTAGES
So that the user is not forced to place external compo-
nents and use up to three pins for bias voltage generation,
internal contrast control and an internal reference ladder
are provided internally. Both of these features may be
used in conjunction with the external VLCD<3:1> pins, to
provide maximum flexibility. Refer to Figure 27-3.
FIGURE 27-3: LCD BIAS VOLTAGE GENERATION BLOCK DIAGRAM
Static Bias 1/2 Bias 1/3 Bias
LCD Bias 0 V
SS VSS VSS
LCD Bias 1 —1/2 VDD 1/3 VDD
LCD Bias 2 —1/2 VDD 2/3 VDD
LCD Bias 3 VLCD3VLCD3VLCD3
VDD
LCDIRE
x 3
3.072V
1.024V from
FVR
VLCD3
LCDIRS
LCDIRE
LCDIRS
LCDCST<2:0>
VLCD3PE
VLCD2
VLCD2PE
VLCD1
VLCD1PE
LCDRLP1
BIASMD
lcdbias3
lcdbias2
lcdbias1
lcdbias0
LCDA
LCDA
LCDA
LCDRLP0