PIC16C925/926
11.4 Operation During SLEEP
The LCD module can operate during SLEEP. The
selection 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
11-8 shows this operation. To ensure that the LCD com-
pletes the frame, the SLEEP instruction should be exe-
cuted immediately after a LCD frame boundary. The
LCD interrupt can be used to determine the frame
boundary. See Section 11.2 for the formulas to calcu-
late the delay.
If a SLEEP instruction is executed and SLPEN = ’0’, the
module will continue to display the current contents of
the LCDD 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 con-
sumption of the device will be lower due to shut-down
of the core and other peripheral functions.
Note:
The internal RC oscillator or external
Timer1 oscillator must be used to operate
the LCD module during SLEEP.
FIGURE 11-8:
SLEEP ENTRY/EXIT WHEN SLPEN = 1 OR CS1:CS0 = 00
Pin
COM0
Pin
COM1
Pin
COM3
Pin
SEG0
Interrupted
Frame
SLEEP Instruction Execution
Wake-up
3/3V
2/3V
1/3V
0/3V
3/3V
2/3V
1/3V
0/3V
3/3V
2/3V
1/3V
0/3V
3/3V
2/3V
1/3V
0/3V
2001 Microchip Technology Inc.
Preliminary
DS39544A-page 93