C8051F99X_10 Datasheet, PDF (29/322 Pages) Silicon Laboratories – Ultra Low Power, 8-2 kB Flash, Capacitive Sensing MCU

C8051F99x-C8051F98x
ADC0MX
Temp
Sensor
P0.1
P0.2
P0.3
P0.4
P0.5
P0.6
P0.7
P1.2
P1.3
*P1.4
AMUX
Digital Supply
Programmable
Attenuator
AIN+
ADC0
Gain = 0.5 or 1
VDD
*Only available on
24-pin devices.
Figure 1.17. ADC0 Multiplexer Block Diagram
1.6. Programmable Current Reference (IREF0)
C8051F99x-C8051F98x devices include an on-chip programmable current reference (source or sink) with
two output current settings: low power mode and high current mode. The maximum current output in low
power mode is 63 µA (1 µA steps) and the maximum current output in high current mode is 504 µA (8 µA
steps).
1.7. Comparator
C8051F99x-C8051F98x devices include an on-chip programmable voltage comparator: Comparator 0
(CPT0) which is shown in Figure 1.18.
The Comparator offers programmable response time and hysteresis, an analog input multiplexer, and two
outputs that are optionally available at the Port pins: a synchronous “latched” output (CP0), or an
asynchronous “raw” output (CP0A). The asynchronous CP0A signal is available even when the system
clock is not active. This allows the Comparator to operate and generate an output when the device is in
some low power modes.
The comparator inputs may be connected to Port I/O pins or to other internal signals. Port pins may also be
used to directly sense capacitive touch switches. See Application Note AN338 for details on Capacitive
Touch Switch sensing.
Rev. 1.0
29