Datasheet

PIC16F193X/LF193X
DS41364D-page 320 Preliminary  2009 Microchip Technology Inc.
25.4 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 CPSRM bit of the CPSCON0 register. See
Section 25.3 “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 25-1 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 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 25-2 shows a more detailed drawing of the
current sources and comparators associated with the
oscillator.
TABLE 25-1: POWER MODE SELECTION
Note: The high power range feature is only avail-
able on the PIC16F/LF1933/1938/1939
devices.
CPSRM
(2)
Range CPSRNG<1:0> Mode Nominal Current
(1)
0 Low
(2)
00 Off 0.0 A
01 Low 0.1 A
10 Medium 1.2 A
11 High 18 A
1 High
(3)
00 Noise Detection 0.0 A
01 Low 9 A
10 Medium 30 A
11 High 100 A
Note 1: See Section 29.0 “Electrical Specifications” for more information.
2: For the PIC16F/LF1934/1936/1937 devices, the Capacitive Sensing Reference Mode bit (CPSRM) of the
CPSCON0 register is not available and the Capacitive Sensing Low Range is the only operable range for
these devices. Different bit configurations made with the CPSRNG<1:0> bits of the CPSCON0 register
make the appropriate selections within the low range only.
3: The Capacitive Sensing High Range is available on the PIC16F1933/1938/1939/PIC16LF1933/1938/1939
devices only.