MC68HC908EY16 Datasheet, PDF (43/278 Pages) Motorola, Inc – Microcontrollers

Chapter 3
Analog-to-Digital Converter (ADC) Module
3.1 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.
3.2 Features
Features of the ADC module include:
• 8 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
3.3 Functional Description
Eight ADC channels are available for sampling external sources at pins PTB7:PTB0. 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 8 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 3-2.
MC68HC908EY16 • MC68HC908EY8 Data Sheet, Rev. 10
Freescale Semiconductor
43