Motorola MC68HC908MR16 用户手册
Advance Information
MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
350
Analog-to-Digital Converter (ADC)
MOTOROLA
Analog-to-Digital Converter (ADC)
If AIEN bit is a logic 1, the COCO is a read/write bit. Reset clears this
bit.
bit.
1 = Conversion completed (AIEN = 0)
0 = Conversion not completed (AIEN = 0)/CPU interrupt (AIEN = 1)
0 = Conversion not completed (AIEN = 0)/CPU interrupt (AIEN = 1)
AIEN — ADC Interrupt Enable Bit
When this bit is set, an interrupt is generated at the end of an ADC
conversion. The interrupt signal is cleared when the data register is
read or the status/control register is written. Reset clears the AIEN bit.
conversion. The interrupt signal is cleared when the data register is
read or the status/control register is written. Reset clears the AIEN bit.
1 = ADC interrupt enabled
0 = ADC interrupt disabled
0 = ADC interrupt disabled
ADCO — ADC Continuous Conversion Bit
When set, the ADC will convert samples continuously and update the
ADR register at the end of each conversion. Only one conversion is
allowed when this bit is cleared. Reset clears the ADCO bit.
ADR register at the end of each conversion. Only one conversion is
allowed when this bit is cleared. Reset clears the ADCO bit.
1 = Continuous ADC conversion
0 = One ADC conversion
0 = One ADC conversion
ADCH[4:0] — ADC Channel Select Bits
ADCH4, ADCH3, ADCH2, ADCH1, and ADCH0 form a 5-bit field
which is used to select one of 10 ADC channels. The ADC channels
are detailed in
which is used to select one of 10 ADC channels. The ADC channels
are detailed in
NOTE:
Take care to prevent switching noise from corrupting the analog signal
when simultaneously using a port pin as both an analog and digital input.
when simultaneously using a port pin as both an analog and digital input.
The ADC subsystem is turned off when the channel select bits are all
set to 1. This feature allows for reduced power consumption for the
MCU when the ADC is not used.
set to 1. This feature allows for reduced power consumption for the
MCU when the ADC is not used.
NOTE:
Recovery from the disabled state requires one conversion cycle to
stabilize.
stabilize.
The voltage levels supplied from internal reference nodes as
specified in
specified in
are used to verify the operation of the ADC
both in production test and for user applications.