s908ey8ad4cfjer Freescale Semiconductor, Inc, s908ey8ad4cfjer Datasheet - Page 45

• Manufacturer Part Number: s908ey8ad4cfjer
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

3.3.1 ADC Port I/O Pins
PTB7:PTB0 are general-purpose I/O pins that are shared with the ADC channels. See
Input/Output (I/O) Ports
The channel select bits define which ADC channel/port pin will be used as the input signal. The ADC
overrides the port logic when that port is selected by the ADC multiplexer. The remaining ADC
channels/port pins are controlled by the port logic and can be used as general-purpose input/output (I/O)
pins. Writes to the port register or DDR will not have any effect 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.
3.3.2 Voltage Conversion
When the input voltage to the ADC equals V
input voltage equals V
straight-line linear conversions. All other input voltages will result in $3FF if greater than V
if less than V
Freescale Semiconductor
INTERNAL
DATA BUS
REFL
AIEN
Input voltage should not exceed the analog supply voltages. See
Analog-to-Digital Converter (ADC)
INTERRUPT
LOGIC
.
READ PTB
BUS CLOCK
COCO/IDMAS
CGMXCLK
REFL
(PORTS).
CONVERSION
COMPLETE
, the ADC converts it to $000. Input voltages between V
MC68HC908EY16 • MC68HC908EY8 Data Sheet, Rev. 10
ADIV[2:0]
Figure 3-2. ADC Block Diagram
GENERATOR
ADC DATA REGISTERS
CLOCK
ADC CLOCK
REFH
ADICLK
ADC
, the ADC converts the signal to $3FF (full scale). If the
NOTE
Characteristics.
ADC VOLTAGE IN
ADVIN
DISABLE
CHANNEL
SELECT
20.10
ADC CHANNEL x
REFH
Functional Description
PTx
PTB
Chapter 12
and V
REFH
ADCH[4:0]
REFL
and $000
are
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