PIC16F1933_11 Datasheet, PDF (325/430 Pages) Microchip Technology – 28-Pin Flash-Based, 8-Bit CMOS Microcontrollers LCD Driver and nanoWatt XLP Technology

PIC16(L)F1933
27.4.3
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 27-7).
The LCDRL register allows switching between two
power modes, designated ‘A’ and ‘B’. ‘A’ Power mode
is active for a programmable time, beginning at the
time when the LCD segments transition. ‘B’ 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 ‘A’ Power mode is active.
Refer to Figure 27-4.
To implement this, the 5-bit prescaler used to divide
the 32 kHz clock down to the LCD controller’s 1 kHz
base rate is used to select the Power mode.
FIGURE 27-4:
LCD INTERNAL REFERENCE LADDER POWER MODE SWITCHING DIAGRAM –
TYPE A
Single Segment Time
32 kHz Clock
Ladder Power
Control
Segment Clock
LRLAT<2:0>
Segment Data
Power Mode
‘H00 ‘H01 ‘H02 ‘H03 ‘H04 ‘H05 ‘H06 ‘H07
LRLAT<2:0>
Power Mode A
‘H3
Power Mode B
COM0
SEG0
COM0-SEG0
‘H0E ‘H0F ‘H00 ‘H01
Mode A
V₁
V₀
V₁
V₀
V₁
V₀
-V₁
 2011 Microchip Technology Inc.
Preliminary
DS41575A-page 325