Chapter 13 Analog-to-Digital Converter (ADC12B16CV1)
MC9S12XE-Family Reference Manual , Rev. 1.19
502
Freescale Semiconductor
13.1.2
Modes of Operation
13.1.2.1
Conversion Modes
There is software programmable selection between performing
single
or
continuous conversion
on a
single channel
or
multiple channels
.
13.1.2.2
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
ADC12B16C behaves same in Run and Wait Mode. For reduced power consumption continuos
conversions should be aborted before entering Wait mode.
•
Freeze Mode
In Freeze Mode the ADC12B16C will either continue or finish or stop converting according to the
FRZ1 and FRZ0 bits. This is useful for debugging and emulation.
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:
S12XE
products
in
208
MAPBGA
packages