s908az32ag2cfue Freescale Semiconductor, Inc, s908az32ag2cfue Datasheet - Page 229

• Manufacturer Part Number: s908az32ag2cfue
• Description: M68hc08 Microcontrollers 8-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Chapter 21
Analog-To-Digital Converter (ADC-15)
21.1 Introduction
This section describes the analog-to-digital converter (ADC-15). The ADC is an 8-bit analog-to-digital
converter.
21.2 Features
Features of the ADC module include:
21.3 Functional Description
Fifteen ADC channels are available for sampling external sources at pins
PTD6/ATD14/TCLK
converter to select one of 15 ADC channels as ADC voltage in (ADCVIN). ADCVIN is converted by the
successive approximation register-based counters. When the conversion is completed, ADC places the
result in the ADC data register and sets a flag or generates an interrupt. See
21.3.1 ADC Port I/O Pins
PTD6/ATD14/TCLK
channels.
The channel select bits define which ADC channel/port pin will be used as the input signal. The ADC
overrides the port I/O logic by forcing that pin as input to the ADC. The remaining ADC channels/port pins
are controlled by the port I/O logic and can be used as general-purpose I/O. Writes to the port register or
DDR will not have any affect on the port pin that is selected by the ADC. Read of a port pin which is in
use by the ADC will return a logic 0 if the corresponding DDR bit is at logic 0. If the DDR bit is at logic 1,
the value in the port data latch is read.
Freescale Semiconductor
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15 Channels with Multiplexed Input
Linear Successive Approximation
8-Bit Resolution
Single or Continuous Conversion
Conversion Complete Flag or Conversion Complete Interrupt
Selectable ADC Clock
Do not use ADC channels ATD14 or ATD12 when using the
PTD6/ATD14/TCLK or PTD4/ATD12 pins as the clock inputs for the 16-bit
Timers.
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PTD0/ATD8 and PTB7
PTD0/ATD8 and PTB7
MC68HC908AZ32A Data Sheet, Rev. 2
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PTB0 are general-purpose I/O pins that share with the ADC
PTB0. An analog multiplexer allows the single ADC
NOTE
Figure
21-1.
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