Datasheet

 2010-2012 Microchip Technology Inc. DS41417B-page 117
PIC16(L)F722A/723A
14.0 CAPACITIVE SENSING
MODULE
The capacitive sensing module allows for an interaction
with an end user without a mechanical interface. In a
typical application, the capacitive sensing module is
attached to a pad on a printed circuit board (PCB), which
is electrically isolated from the end user. When the end
user places their finger over the PCB pad, a capacitive
load is added, causing a frequency shift in the capacitive
sensing module. The capacitive sensing module
requires software and at least one timer resource to
determine the change in frequency. Key features of this
module include:
• Analog MUX for monitoring multiple inputs
• Capacitive sensing oscillator
• Multiple timer resources
• Software control
• Operation during Sleep
FIGURE 14-1: CAPACITIVE SENSING BLOCK DIAGRAM
T0CS
CPS0
CPS1
CPS2
CPS3
CPS4
CPS5
CPS6
CPS7
CPSCH<2:0>
Capacitive
Sensing
Oscillator
CPSOSC
CPSON
CPSRNG<1:0>
TMR0
0
1
Set
T0IF
Overflow
T0XCS
0
1
T0CKI
T1CS<1:0>
T1OSC/
T1CKI
TMR1H:TMR1L
EN
T1GSEL<1:0>
Timer1 Gate
Control Logic
T1G
CPSOUT
TMR2
Timer2 Module
Set
TMR2IF
Overflow
Postscaler
CPSCLK
Note 1: If CPSON = 0, disabling capacitive sensing, no channel is selected.
FOSC/4
F
OSC
FOSC/4
Timer0 Module
Timer1 Module
CPSON
(1)
WDT
WDT
Event
Overflow
Watchdog Timer Module
Scaler
PS<2:0>
LP WDT
OSC