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74 lines
2.9 KiB
74 lines
2.9 KiB
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ADC Synchronous driver
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An ADC (Analog-to-Digital Converter) converts analog signals to digital values.
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A reference signal with a known voltage level is quantified into equally
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sized chunks, each representing a digital value from 0 to the highest number
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possible with the bit resolution supported by the ADC. The input voltage
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measured by the ADC is compared against these chunks and the chunk with the
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closest voltage level defines the digital value that can be used to represent
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the analog input voltage level.
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Usually an ADC can operate in either differential or single-ended mode.
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In differential mode two signals (V+ and V-) are compared against each other
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and the resulting digital value represents the relative voltage level between
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V+ and V-. This means that if the input voltage level on V+ is lower than on
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V- the digital value is negative, which also means that in differential
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mode one bit is lost to the sign. In single-ended mode only V+ is compared
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against the reference voltage, and the resulting digital value can only be
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positive, but the full bit-range of the ADC can be used.
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Usually multiple resolutions are supported by the ADC, lower resolution can
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reduce the conversion time, but lose accuracy.
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Some ADCs has a gain stage on the input lines which can be used to increase the
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dynamic range. The default gain value is usually x1, which means that the
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conversion range is from 0V to the reference voltage.
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Applications can change the gain stage, to increase or reduce the conversion
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range.
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The window mode allows the conversion result to be compared to a set of
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predefined threshold values. Applications can use callback function to monitor
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if the conversion result exceeds predefined threshold value.
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Usually multiple reference voltages are supported by the ADC, both internal and
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external with difference voltage levels. The reference voltage have an impact
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on the accuracy, and should be selected to cover the full range of the analog
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input signal and never less than the expected maximum input voltage.
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There are two conversion modes supported by ADC, single shot and free running.
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In single shot mode the ADC only make one conversion when triggered by the
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application, in free running mode it continues to make conversion from it
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is triggered until it is stopped by the application. When window monitoring,
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the ADC should be set to free running mode.
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Features
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--------
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* Initialization and de-initialization
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* Support multiple Conversion Mode, Single or Free run
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* Start ADC Conversion
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* Read Conversion Result
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Applications
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* Measurement of internal sensor. E.g., MCU internal temperature sensor value.
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* Measurement of external sensor. E.g., Temperature, humidity sensor value.
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* Sampling and measurement of a signal. E.g., sinusoidal wave, square wave.
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Dependencies
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* ADC hardware
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Concurrency
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N/A
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Limitations
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-----------
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N/A
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Knows issues and workarounds
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N/A
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