MC68HC908MR8 Datasheet, PDF (312/372 Pages) Motorola, Inc – Microcontrollers

Analog-to-Digital Converter (ADC)
18.2 Introduction
This section describes the 10-bit analog-to-digital converter (ADC).
For further information regarding analog-to-digital converters on
Freescale microcontrollers, please consult the HC08 ADC Reference
Manual, ADCRM/AD.
18.3 Features
Features of the ADC module include:
• Four to seven channels with multiplexed input
• Linear successive approximation
• 10-bit resolution, 8-bit accuracy
• Single or continuous conversion
• Conversion complete flag or conversion complete interrupt
• Selectable ADC clock
• Left or right justified result.
• Left justified sign data mode
• High impedance buffered ADC input
18.4 Functional Description
Depending on the package option, up to seven ADC channels are
available for sampling external sources at pins PTA6/ATD6:PT00/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 seven 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 Figure 18-1.
Technical Data
312
Analog-to-Digital Converter (ADC)
MC68HC908MR8 — Rev 4.1
Freescale Semiconductor