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PIC18F6390 Datasheet, PDF (279/412 Pages) Microchip Technology – 64/80-Pin Flash Microcontrollers with LCD Driver and nanoWatt Technology
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PIC18F6390/6490/8390/8490
22.10 Operation During Sleep
The LCD module can operate during Sleep. The selec-
tion is controlled by bit SLPEN (LCDCON<6>). Setting
the SLPEN bit allows the LCD module to go to Sleep.
Clearing the SLPEN bit allows the module to continue
to operate during Sleep.
If a SLEEP instruction is executed and SLPEN = 1, the
LCD module will cease all functions and go into a very
low current consumption mode. The module will stop
operation immediately and drive the minimum LCD
voltage on both segment and common lines.
Figure 22-16 shows this operation.
To ensure that no DC component is introduced on the
panel, the SLEEP instruction should be executed imme-
diately after a LCD frame boundary. The LCD interrupt
can be used to determine the frame boundary. See
Section 22.9 “LCD Interrupts” for the formulas to
calculate the delay.
If a SLEEP instruction is executed and SLPEN = 0, the
module will continue to display the current contents of
the LCDDATA registers. To allow the module to
continue operation while in Sleep, the clock source
must be either the internal RC oscillator or Timer1
external oscillator. While in Sleep, the LCD data cannot
be changed. The LCD module current consumption will
not decrease in this mode; however, the overall
consumption of the device will be lower due to shut
down of the core and other peripheral functions.
If the system clock is selected and the module is
programmed to not Sleep, the module will ignore the
SLPEN bit and stop operation immediately. The
minimum LCD voltage will then be driven onto the
segments and commons.
Note:
The internal RC oscillator or external
Timer1 oscillator must be used to operate
the LCD module during Sleep.
FIGURE 22-16: SLEEP ENTRY/EXIT WHEN SLPEN = 1 OR CS1:CS0 = 00
V3
V2
V1
COM0
V0
V3
V2
V1
COM1
V0
V3
V2
V1
COM2
V0
V3
V2
V1
SEG0
V0
2 Frames
SLEEP Instruction Execution
Wake-up
 2004 Microchip Technology Inc.
Preliminary
DS39629B-page 277
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