PIC16F707 Datasheet, PDF (121/284 Pages) Microchip Technology – 40/44-Pin, Flash Microcontrollers with nanoWatt XLP and mTouch™ Technology

PIC16F707/PIC16LF707
16.4 Power Modes
The capacitive sensing oscillator can operate in one of
seven different power modes. The power modes are
separated into two ranges; the low range and the high
range.
When the oscillator's low range is selected, the fixed
internal voltage references of the capacitive sensing
oscillator are being used. When the oscillator's high
range is selected, the variable voltage references
supplied by the FVR and DAC modules are being used.
Selection between the voltage references is controlled
by the CPSxRM bit of the CPSxCON0 register. See
Section 16.3 “Voltage References” for more
information.
Within each range there are three distinct power
modes; Low, Medium and High. Current consumption
is dependent upon the range and mode selected.
Selecting power modes within each range is accom-
plished by configuring the CPSxRNG <1:0> bits in the
CPSxCON0 register. See Table 16-2 for proper power
mode selection.
The remaining mode is a Noise Detection mode that
resides within the high range. The Noise Detection
mode is unique in that it disables the sinking and sourc-
ing of current on the analog pin but leaves the rest of
the oscillator circuitry active. This reduces the oscilla-
tion frequency on the analog pin to zero and also
greatly reduces the current consumed by the oscillator
module.
When noise is introduced onto the pin, the oscillator is
driven at the frequency determined by the noise. This
produces a detectable signal at the comparator output,
indicating the presence of activity on the pin.
Figure 16-2 shows a more detailed drawing of the
current sources and comparators associated with the
oscillator.
TABLE 16-2: POWER MODE SELECTION
CPSxRM
Range
CPSxRNG<1:0>
Mode
Nominal Current ⁽¹⁾
00
Off
0
Low
01
Low
10
Medium
11
High
00
Noise Detection
1
High
01
Low
10
Medium
11
High
Note: See Section 25.0 “Electrical Specifications” for more information.
0.0 µA
0.1 µA
1.2 µA
18 µA
0.0 µA
9 µA
30 µA
100 µA
16.5 Timer Resources
To measure the change in frequency of the capacitive
sensing oscillator, a fixed time base is required. For the
period of the fixed time base, the capacitive sensing
oscillator is used to clock either TimerA/B or Timer1/3
(for CPSA/B, respectively). The frequency of the
capacitive sensing oscillator is equal to the number of
counts in the timer divided by the period of the fixed
time base.
16.6 Fixed Time Base
To measure the frequency of the capacitive sensing
oscillator, a fixed time base is required. Any timer
resource or software loop can be used to establish the
fixed time base. It is up to the end user to determine the
method in which the fixed time base is generated.
Note:
The fixed time base can not be generated
by the timer resource that the capacitive
sensing oscillator is clocking.
 2010 Microchip Technology Inc.
Preliminary
DS41418A-page 121