Ublox NINA-B3 Series, System Integration Manual

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NINA-B3 series - System integration manual
UBX-17056748 - R13 System description Page 13 of 72
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1.8.1 Analog interfaces
Eight out of the 38 digital GPIOs can be multiplexed to analog functions. The following analog
functions are available for use:
• 1x 8-channel ADC
• 1x Analog comparator*
• 1x Low-power analog comparator*
*Only one of the comparators can be used simultaneously.
ADC
The Analog to Digital Converter (ADC) can sample up to 200 kHz using different inputs as sample
triggers. Both one-shot conversion and continuous sampling are supported.
Table 5 shows the
sample speed in correlation to the maximum source impedance. It supports 8/10/12-bit resolution.
The ADC includes 14-bit resolution if oversampling is used. Any of the 8 analog inputs can be used
both as single-ended inputs and as differential pairs for measuring the voltage across them.
The ADC supports the full 0 V to VCC input range. If the sampled signal level is much lower than VCC ,
it is possible to lower the input range of the ADC to encompass the desired signal and obtain a higher
effective resolution. Continuous sampling can be configured to sample at a configurable time interval,
or at different internal or external events, without CPU involvement.
Table 5: Acquisition vs. source impedance
Comparator
The comparator compares voltages from any analog pin with different references as shown in Table
6. It supports the full 0 V to VCC input range and can generate different software events to the rest
of the system. The comparator can operate in the one of the following two modes as explained below
- Single-ended or Differential:
• Single-ended Mode: A single reference level or an upper and lower hysteresis selectable from a
64-level reference ladder with a range from 0 V to VREF as described in
Table 6 .
• Differential Mode: Two analog pin voltage levels are compared, optionally with a 50 mV hysteresis
Low power comparator
The low-power comparator operates in the same way as the normal comparator, with reduced
functionality. It can be used during system OFF modes as a wake-up source.
Analog pin options
Table 6 shows the supported connections of the analog functions.
☞
An analog pin may not be simultaneously connected to multiple functions.
ACQ [us] Maximum source resistance [k
Ω
]
3 10
5 40
10 100
15 200
20 400
40 800