MA180025 Microchip Technology, MA180025 Datasheet - Page 191

• Manufacturer Part Number: MA180025
• Description: MODULE PLUG-IN PIC18F87J90 PIM
• Manufacturer: Microchip Technology
• Series: PIC®r

Specifications of MA180025

• Accessory Type: Plug-In Module (PIM) - PIC18F87J90
• Product: Microcontroller Modules
• Silicon Manufacturer: Microchip
• Core Architecture: PIC
• Core Sub-architecture: PIC18
• Silicon Core Number: PIC18F
• Silicon Family Name: PIC18FxxJxx
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: PICDEM LCD 2 Demonstration Board (DM163030)
• For Use With: DM163030 - KIT DEV PICDEM LCD2
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

17.3.3.3
M2 operation also uses the LCD regulator but disables
the charge pump. The regulator’s internal voltage refer-
ence remains active as a way to regulate contrast. It is
used in cases where the current requirements of the
LCD exceed the capacity of the regulator’s charge
pump.
In this configuration, the LCD bias voltage levels are
created by an external resistor voltage divider,
connected across LCDBIAS0 through LCDBIAS3, with
the top of the divider tied to V
potential at the bottom of the ladder is determined by
the LCD regulator’s voltage reference, tied internally to
LCDBIAS0. The bias type is determined by the volt-
ages on the LCDBIAS pins, which are controlled by the
FIGURE 17-4:
 2010 Microchip Technology Inc.
Note 1: These values are provided for design guidance only; they should be optimized for the application by the designer
M2 (Resistor Ladder with
Software Contrast)
based on the actual LCD specifications.
Bias Level at Pin
LCDBIAS0
LCDBIAS1
LCDBIAS2
LCDBIAS3
PIC18F87J90
RESISTOR LADDER CONNECTIONS FOR M2 CONFIGURATION
LCDBIAS3
LCDBIAS2
LCDBIAS1
LCDBIAS0
DD
AV
(Figure 17-4). The
DD
V
(Internal Low Reference Voltage)
DD
1/2 Bias
V
BIAS
10 k
10 k
1/2 V
1/2 V
1/2 Bias
(up to AV
BIAS
BIAS
(1)
(1)
PIC18F87J90 FAMILY
configuration of the resistor ladder. Most applications
using M2 will use a 1/3 or 1/2 Bias type. While Static
Bias can also be used, it offers extremely limited
contrast range and additional current consumption
over other bias generation modes.
Like M1, the LCDBIAS bits can be used to control con-
trast, limited by the level of V
Also, since there is no capacitor required across
V
I/O ports, RG2 and RG3.
M2 is selected by clearing the CKSEL<1:0> bits and
setting the CPEN bit.
DD
LCAP
)
1 and V
Bias Type
LCAP
(Internal Low Reference Voltage)
2, these pins are available as digital
V
BIAS
1/3 V
2/3 V
1/3 Bias
DD
(up to AV
1/3 Bias
supplied to the device.
BIAS
BIAS
DS39933D-page 191
10 k
10 k
10 k
DD
)
(1)
(1)
(1)