PIC16LF1824T39A_12 Datasheet, PDF (314/418 Pages) Microchip Technology – 20-Pin Flash Microcontrollers with XLP Technology

PIC16LF1824T39A
27.4 Current Ranges
The Capacitive Sensing Oscillator can operate within
several different current ranges, depending on the
voltage reference mode and current range selections.
Within each of the two voltage reference modes there
are four current ranges.
Selection between the voltage reference modes is
controlled by the CPSRM bit of the CPSCON0
register. Clearing this bit selects the fixed voltage
references provided by the capacitive sensing
oscillator module. Setting this bit selects the variable
voltage references supplied by the Fixed Voltage
Reference (FVR) module and the Digital-to-Analog
Converter (DAC) module. See Section 27.3 “Voltage
Reference Modes” for more information on
configuring the voltage references. Selecting the
current range within the voltage reference mode is
controlled by configuring the CPSRNG<1:0> bits in the
CPSCON0 register. See Table 27-1 for proper current
mode selection.
The Noise Detection mode is unique in that it disables
the constant current source associated with the
selected input pin, but leaves the rest of the oscillator
circuitry and pin structure active. This eliminates the
oscillation frequency on the analog pin and 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 stage, indicating the presence of activity
on the pin. Figure 27-2 shows a more detailed drawing
of the constant current sources and comparators
associated with the oscillator and input pin.
TABLE 27-1: CURRENT MODE SELECTION
CPSRM
Voltage Reference
Mode
CPSRNG<1:0>
Current Range
00
Off
0
Fixed
01
Low
10
Medium
11
High
00
Noise Detection
1
Variable
01
Low
10
Medium
11
High
Note 1: See Section 31.0 “Electrical Specifications” for more information.
Nominal Current⁽¹⁾
0.0 A
0.1 A
1.2 A
18 A
0.0 A
9 A
30 A
100 A
DS41657A-page 314
Preliminary
 2012 Microchip Technology Inc.