Freescale Semiconductor MC68HC908MR32 Manual Do Utilizador
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
Freescale Semiconductor
45
Chapter 3
Analog-to-Digital Converter (ADC)
Analog-to-Digital Converter (ADC)
3.1 Introduction
This section describes the 10-bit analog-to-digital converter (ADC).
3.2 Features
Features of the ADC module include:
•
10 channels with multiplexed input
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Linear successive approximation
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10-bit resolution, 8-bit accuracy
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Single or continuous conversion
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Conversion complete flag or conversion complete interrupt
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Selectable ADC clock
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Left or right justified result
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Left justified sign data mode
•
High impedance buffered ADC input
3.3 Functional Description
Ten ADC channels are available for sampling external sources at pins PTC1/ATD9:PTC0/ATD8 and
PTB7/ATD7:PTB0/ATD0. To achieve the best possible accuracy, these pins are implemented as
input-only pins when the analog-to-digital (A/D) feature is enabled. An analog multiplexer allows the single
ADC to select one of the 10 ADC channels as ADC voltage IN (ADCVIN). ADCVIN is converted by the
successive approximation algorithm. When the conversion is completed, the ADC places the result in the
ADC data register (ADRH and ADRL) and sets a flag or generates an interrupt. See
PTB7/ATD7:PTB0/ATD0. To achieve the best possible accuracy, these pins are implemented as
input-only pins when the analog-to-digital (A/D) feature is enabled. An analog multiplexer allows the single
ADC to select one of the 10 ADC channels as ADC voltage IN (ADCVIN). ADCVIN is converted by the
successive approximation algorithm. When the conversion is completed, the ADC places the result in the
ADC data register (ADRH and ADRL) and sets a flag or generates an interrupt. See