C8051F80x-83x
13. Capacitive Sense (CS0)
The Capacitive Sense subsystem included on the C8051F800/1/3/4/6/7/9, C8051F810/2/3/5/6/8/9,
C8051F821/2/4/5/7/8, C8051F830/1/3/4 uses a capacitance-to-digital circuit to determine the capacitance
on a port pin. The module can take measurements from different port pins using the module’s analog mul-
tiplexer. The multiplexer supports up to 16 channels. See SFR Definition 13.9. “CS0MX: Capacitive Sense
only when the CS0EN bit (CS0CN) is set to 1. Otherwise the module is in a low-power shutdown state. The
module can be configured to take measurements on one port pin or a group of port pins, using auto-scan.
An accumulator can be configured to accumulate multiple conversions on an input channel. Interrupts can
be generated when CS0 completes a conversion or when the measured value crosses a threshold defined
in CS0THH:L.
CS0CN
CS0INT
CS0BUSY
CS0CMPEN
CS0CMPF
CS0EN
CS0CF
CS0ACU2
CS0ACU1
CS0ACU0
CS0CM2
CS0CM1
CS0CM0
000
001
010
011
100
101
110
111
CS0SS
CS0SE
CS0BUSY (W)
Timer 0 Overflow
Timer 2 Overflow
Timer 1 Overflow
Reserved
Reserved
Initiated continuously
Initiated continuously
when auto-scan
enabled
Auto-Scan
Logic
Start
Conversion
CS0MX
AMUX
16-Bit
Capacitance to
Digital Converter
22-Bit Accumulator
...
CS0DH:L
Greater Than
Compare Logic
CS0CMPF
CS0THH:L
Figure 13.1. CS0 Block Diagram
Rev. 1.0
71
SILABS [ SILICON LABORATORIES ]
