C8051F99X_10 Datasheet, PDF (81/322 Pages) Silicon Laboratories – Ultra Low Power, 8-2 kB Flash, Capacitive Sensing MCU

C8051F99x-C8051F98x
5.7. ADC0 Analog Multiplexer
ADC0 on C8051F99x-C8051F98x has an analog multiplexer, referred to as AMUX0.
AMUX0 selects the positive inputs to the single-ended ADC0. Any of the following may be selected as the
positive input: Port I/O pins, the on-chip temperature sensor, Regulated Digital Supply Voltage (Output of
VREG0), VDD Supply, or the positive input may be connected to GND. The ADC0 input channels are
selected in the ADC0MX register described in SFR Definition 5.12.
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 5.7. ADC0 Multiplexer Block Diagram
Important Note About ADC0 Input Configuration: Port pins selected as ADC0 inputs should be
configured as analog inputs, and should be skipped by the Digital Crossbar. To configure a Port pin for
analog input, set to 0 the corresponding bit in register PnMDIN and disable the digital driver (PnMDOUT =
0 and Port Latch = 1). To force the Crossbar to skip a Port pin, set to 1 the corresponding bit in register
PnSKIP. See Section “21. Port Input/Output” on page 213 for more Port I/O configuration details.
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