PIC16F/LF1826/27
26.0 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 26-1:
CAPACITIVE SENSING BLOCK DIAGRAM
CPS0
CPS1
CPS2
CPS3
CPS4
CPS5
CPS6
CPS7
CPS8
CPS9
CPS10
CPS11
CPSCH<3:0>
CPSON(1)
T0XCS
T0CKI
0
1
Timer0 Module
TMR0CS
FOSC/4 0
1
TMR0
Overflow
Set
TMR0IF
CPSON
Capacitive
Sensing
Oscillator
CPSOSC
CPSCLK
CPSOUT
CPSRNG<1:0>
T1CS<1:0>
FOSC
FOSC/4
T1OSC/
T1CKI
T1GSEL<1:0>
T1G
SYNCC1OUT
SYNCC2OUT
Timer1 Module
TMR1H:TMR1L
EN
Timer1 Gate
Control Logic
Note 1: If CPSON = 0, disabling capacitive sensing, no channel is selected.
2010 Microchip Technology Inc.
Preliminary
DS41391C-page 317