PIC16F946 Datasheet, PDF (127/274 Pages) Microchip Technology – 64-Pin Flash-Based, 8-Bit CMOS Microcontrollers with LCD Driver and nanoWatt Technology

9.9 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 9-18 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 9.8 “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 LFINTOSC or T1OSC 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.
Table 9-4 shows the status of the LCD module during
a Sleep while using each of the three available clock
sources:
TABLE 9-4: LCD MODULE STATUS
DURING SLEEP
Clock Source
SLPEN
Operation
During Sleep?
T1OSC
0
Yes
1
No
0
Yes
LFINTOSC
1
No
FOSC/4
0
No
1
No
Note:
The LFINTOSC or external T1OSC
oscillator must be used to operate the LCD
module during Sleep.
PIC16F946
© 2005 Microchip Technology Inc.
Preliminary
DS41265A-page 125