mc68hc908lb8 Freescale Semiconductor, Inc, mc68hc908lb8 Datasheet - Page 46

• Manufacturer Part Number: mc68hc908lb8
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Analog-to-Digital Converter (ADC)
3.2 Features
Features of the ADC module include:
3.3 Functional Description
Seven ADC channels are available for sampling external sources at pins PTB7/ADC6, PTA6/ADC5,
PTA4/ADC4–PTA0/ADC0. An analog multiplexer allows a single ADC converter to select one of seven
ADC channels as ADC voltage in (ADCVIN). ADCVIN is converted by the successive approximation
register based counters. When the conversion is complete, ADC places the result in the ADC data register
and sets a flag or generates an interrupt.
See
3.3.1 ADC Port I/O Pins
PTB7/ADC6, PTA6/ADC5, PTA4/ADC4–PTA0/ADC0 are general-purpose I/O (input/output) pins that
share with the ADC channels. The channel select bits define which ADC channel/port pin will be used as
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Figure
7 channels with multiplexed input
Linear successive approximation
8-bit resolution
Single or continuous conversion
Conversion complete flag or conversion complete interrupt
Selectable ADC clock
3-2.
INTERNAL DATA BUS
AIEN
INTERRUPT
LOGIC
COCO
READ DDRAx/DDRBx
WRITE DDRAx/DDRBx
WRITE PTAx/PTBx
READ PTAx/PTBx
CONVERSION
BUS CLOCK
COMPLETE
RESET
Figure 3-2. ADC Block Diagram
MC68HC908LB8 Data Sheet, Rev. 1
ADC DATA REGISTER
DDRAx/DDRAx
PTAx/PTBx
GENERATOR
ADIV[2:0]
CLOCK
ADC
ADC CLOCK
VOLTAGE IN
(V
ADC
ADIN
DISABLE
)
DISABLE
CHANNEL
SELECT
ADC CHANNEL x
PTAx/PTBx
ADCH[4:0]
Freescale Semiconductor