Analog-to-Digital Converter (ADC12B12CV1) Block Description
MC9S12XHY-Family Reference Manual, Rev. 1.01
Freescale Semiconductor
317
10.1.2
Modes of Operation
10.1.2.1
Conversion Modes
There is software programmable selection between performing
single
or
continuous conversion
on a
single channel
or
multiple channels
.
10.1.2.2
MCU Operating Modes
•
Stop Mode
—
ICLKSTP=0 (in ATDCTL2 register)
Entering Stop Mode aborts any conversion sequence in progress and if a sequence was aborted
restarts it after exiting stop mode. This has the same effect/consequences as starting a
conversion sequence with write to ATDCTL5. So after exiting from stop mode with a
previously aborted sequence all flags are cleared etc.
—
ICLKSTP=1 (in ATDCTL2 register)
A/D conversion sequence seamless continues in Stop Mode based on the internally generated
clock ICLK as ATD clock. For conversions during transition from Run to Stop Mode or vice
versa the result is not written to the results register, no CCF flag is set and no compare is done.
When converting in Stop Mode (ICLKSTP=1) an ATD Stop Recovery time
t
ATDSTPRCV
is
required to switch back to bus clock based ATDCLK when leaving Stop Mode. Do not access
ATD registers during
this time
.
•
Wait Mode
ADC12B12C behaves same in Run and Wait Mode. For reduced power consumption continuous
conversions should be aborted before entering Wait mode.
•
Freeze Mode
In Freeze Mode the ADC12B12C will either continue or finish or stop converting according to the
FRZ1 and FRZ0 bits. This is useful for debugging and emulation.
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