PIC16F1847_13 Datasheet, PDF (320/440 Pages) Microchip Technology – 18/20/28-Pin Flash Microcontrollers with XLP Technology

PIC16(L)F1847
27.4 Current Ranges
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 CPSRM bit of the CPSCON0 register. See
Section 27.3 “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 accomplished by configuring
the CPSRNG <1:0> bits in the CPSCON0 register. See
Table 27-1 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
sourcing of current on the analog pin but leaves the rest
of the oscillator circuitry active. This reduces the
oscillation 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 27-1 shows a more detailed drawing of the
current sources and comparators associated with the
oscillator.
TABLE 27-1: CURRENT RANGE MODE SELECTION
CPSRM
Range
CPSRNG<1:0>
Current Range⁽¹⁾
Note 1:
00
Noise Detection
1
Variable
01
10
Low
Medium
11
High
00
Off
0
Fixed
01
10
Low
Medium
11
High
See Power-Down Currents (IPD) in Section 30.0 “Electrical Specifications” for more information.
DS40001453D-page 320
Preliminary
 2011-2013 Microchip Technology Inc.