Microchip Technology AC244055 Data Sheet
2011-2013 Microchip Technology Inc.
DS40001574C-page 315
PIC16(L)F1938/9
26.0 CAPACITIVE SENSING (CPS)
MODULE
The Capacitive Sensing (CPS) module allows for an
interaction with an end user without a mechanical
interface. In a typical application, the CPS 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
CPS module. The CPS 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 Current Ranges
• Multiple Voltage Reference modes
• Multiple timer resources
• Software control
• Operation during Sleep
interaction with an end user without a mechanical
interface. In a typical application, the CPS 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
CPS module. The CPS 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 Current Ranges
• Multiple Voltage Reference modes
• Multiple timer resources
• Software control
• Operation during Sleep
FIGURE 26-1:
CAPACITIVE SENSING BLOCK DIAGRAM
TMR0CS
CPS0
CPS1
CPS2
CPS3
CPS4
CPS5
CPS6
CPS7
CPS1
CPS2
CPS3
CPS4
CPS5
CPS6
CPS7
CPS8
(1)
CPS9
(1)
CPS10
(1)
CPSCH<3:0>
Capacitive
Sensing
Oscillator
CPSOSC
CPSOSC
CPSON
CPSRNG<1:0>
TMR0
0
1
Set
TMR0IF
Overflow
T0XCS
0
1
T0CKI
CPS11
(1)
CPS12
(1)
CPS13
(1)
CPS14
(1)
CPS15
(1)
CPSCLK
Note 1:
Reference CPSCON1 register (
) for channels implemented on each device.
2:
If CPSON = 0, disabling capacitive sensing, no channel is selected.
F
OSC
/4
Timer0 Module
CPSON
(2)
TMR1CS<1:0>
T1OSC/
T1CKI
TMR1H:TMR1L
EN
T1GSEL<1:0>
Timer1 Gate
Control Logic
T1G
F
OSC
F
OSC
/4
Timer1 Module
sync_C1OUT
sync_C2OUT
sync_C2OUT
0
1
Int.
Ref.
FVR
DAC
Ref+
Ref-
CPSRM
0
1
CPSOUT
Output