Ublox NINA-B4 Series, Руководство по системной интеграции, Страница: 20 / 61

NINA-B4 series - System integration manual
UBX-19052230 - R09 Design-in Page 20 of 61
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2.5.1 Analog interfaces
NINA-B40 modules have 40 GPIO pins, 10 of which 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.
For further information about the support for analog interfaces, see also the NINA-B40 data sheet [2] .
☞
NINA-B41 modules have no support for analog interfaces.
2.5.1.1 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 12 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 12: Acquisition versus source impedance
2.5.1.2 Comparator
The comparator compares voltages from any analog pin with different references as shown in Table
13. 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,
this is, 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 13 .
• Differential mode: Two analog pin voltage levels are compared, optionally with a 50 mV hysteresis.
2.5.1.3 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.
ACQ [us] Maximum source resistance [k
Ω
]
3 10
5 40
10 100
15 200
20 400
40 800