PIC16F913/914/916/917/946
Table 10-5 shows the status of the LCD module during
a Sleep while using each of the three available clock
sources:
10.10 Operation During Sleep
The LCD module can operate during Sleep. The
selection is controlled by bit SLPEN of the LCDCON
register. 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.
TABLE 10-5: LCD MODULE STATUS
DURING SLEEP
Operation
During Sleep?
If a SLEEPinstruction 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 10-18 shows this operation.
Clock Source
T1OSC
SLPEN
0
1
0
1
0
1
Yes
No
Yes
No
No
No
LFINTOSC
FOSC/4
To ensure that no DC component is introduced on the
panel, the SLEEP instruction should be executed
immediately after a LCD frame boundary. For Type-B
multiplex (non-static), the LCD interrupt can be used to
determine the frame boundary. See Section 10.9
“LCD Interrupts” for the formulas to calculate the
delay. In all other modes, the LCDA bit can be used to
determine when the display is active. To use this
method, the following sequence should be used when
wanting to enter into Sleep mode:
Note:
The LFINTOSC or external T1OSC
oscillator must be used to operate the LCD
module during Sleep.
If LCD interrupts are being generated (Type-B wave-
form with a multiplex mode not static) and LCDIE = 1,
the device will awaken from Sleep on the next frame
boundary.
• Clear LCDEN
• Wait for LCDA to clear
• Drive all LCD pins to inactive state using PORT
and TRIS registers
• Execute SLEEPinstruction
Note:
When the LCDEN bit is cleared, the LCD
module will be disabled at the completion
of frame. At this time, the PORT pins will
revert to digital functionality. To minimize
power consumption due to floating digital
inputs, the LCD pins should be driven low
using the PORT and TRIS registers.
If a SLEEPinstruction 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.
© 2007 Microchip Technology Inc.
DS41250F-page 165
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