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PIC16F1946 Datasheet, PDF (339/440 Pages) Microchip Technology – 64-Pin Flash-Based, 8-Bit CMOS Microcontrollers with LCD Driver and nanoWatt XLP Technology | |||
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PIC16F/LF1946/47
26.4.3 AUTOMATIC POWER MODE
SWITCHING
As an LCD segment is electrically only a capacitor, cur-
rent is drawn only during the interval where the voltage
is switching. To minimize total device current, the LCD
internal reference ladder can be operated in a different
power mode for the transition portion of the duration.
This is controlled by the LCDRL Register
(Register 26-7).
The LCDRL register allows switching between two
power modes, designated âAâ and âBâ. âAâ Power mode
is active for a programmable time, beginning at the
time when the LCD segments transition. âBâ Power
mode is the remaining time before the segments or
commons change again. The LRLAT<2:0> bits select
how long, if any, that the âAâ Power mode is active.
Refer to Figure 26-4.
To implement this, the 5-bit prescaler used to divide
the 32 kHz clock down to the LCD controllerâs 1 kHz
base rate is used to select the power mode.
FIGURE 26-4:
LCD INTERNAL REFERENCE LADDER POWER MODE SWITCHING DIAGRAM â
TYPE A
Single Segment Time
32 kHz Clock
Ladder Power
Control
Segment Clock
LRLAT<2:0>
Segment Data
Power Mode
âH00 âH01 âH02 âH03 âH04 âH05 âH06 âH07
LRLAT<2:0>
Power Mode A
âH3
Power Mode B
COM0
SEG0
COM0-SEG0
âH0E âH0F âH00 âH01
Mode A
V1
V0
V1
V0
V1
V0
-V1
ï£ 2010 Microchip Technology Inc.
Preliminary
DS41414A-page 337
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