Datasheet

© 2007 Microchip Technology Inc. DS41250F-page 167
PIC16F913/914/916/917/946
10.11 Configuring the LCD Module
The following is the sequence of steps to configure the
LCD module.
1. Select the frame clock prescale using bits
LP<3:0> of the LCDPS register.
2. Configure the appropriate pins to function as
segment drivers using the LCDSEn registers.
3. Configure the LCD module for the following
using the LCDCON register:
- Multiplex and Bias mode, bits LMUX<1:0>
- Timing source, bits CS<1:0>
- Sleep mode, bit SLPEN
4. Write initial values to pixel data registers,
LCDDATA0 through LCDDATA11 (LCDDATA23
on PIC16F946).
5. Clear LCD Interrupt Flag, LCDIF bit of the PIR2
register and if desired, enable the interrupt by
setting bit LCDIE of the PIE2 register.
6. Enable bias voltage pins (VLCD<3:1>) by
setting bit VLCDEN of the LCDCON register.
7. Enable the LCD module by setting bit LCDEN of
the LCDCON register.
10.12 Disabling the LCD Module
To disable the LCD module, write all ‘0’s to the
LCDCON register.
10.13 LCD Current Consumption
When using the LCD module the current consumption
consists of the following three factors:
1. The oscillator selected
2. The LCD bias source
3. The current required to charge the LCD
segments
The current consumption of just the LCD module can
be considered negligible compared to these other
factors.
The oscillator selected:
For LCD operation during Sleep either the T1oc or the
LFINTOSC sources need to be used as the main
system oscillator may be disabled during Sleep. During
Sleep the LFINTOSC current consumption is given by
electrical parameter D021, where the LFINTOSC use
the same internal oscillator circuitry as the Watchdog
Timer.
The LCD bias source:
The LCD bias source, typically an external resistor
ladder which will have its own current draw.
The current required to charge the LCD segments:
The LCD segments which can be modeled as capaci-
tors which must be both charged and discharged every
frame. The size of the LCD segment and its technology
determines the segment’s capacitance.