s908qc16g0cdte Freescale Semiconductor, Inc, s908qc16g0cdte Datasheet - Page 39

• Manufacturer Part Number: s908qc16g0cdte
• Description: M68hc08 Family Of 8-bit Microcontroller Units Mcus
• Manufacturer: Freescale Semiconductor, Inc

To protect status bits during the break state, write a 0 to BCFE. With BCFE cleared (its default state),
software can read and write registers during the break state without affecting status bits. Some status bits
have a two-step read/write clearing procedure. If software does the first step on such a bit before the
break, the bit cannot change during the break state as long as BCFE is cleared. After the break, doing the
second step clears the status bit.
3.7 I/O Signals
The ADC10 module shares its pins with general-purpose input/output (I/O) port pins. See
port location of these shared pins. The ADC10 on this MCU uses V
pins. This MCU does not have an external trigger source.
3.7.1 ADC10 Analog Power Pin (V
The ADC10 analog portion uses V
to V
may be necessary to ensure clean V
3.7.2 ADC10 Analog Ground Pin (V
The ADC10 analog portion uses V
to V
In cases where separate power supplies are used for analog and digital power, the ground connection
between these supplies should be at the V
these supplies if possible. The V
3.7.3 ADC10 Voltage Reference High Pin (V
V
V
potential as V
the V
AC current in the form of current spikes required to supply charge to the capacitor array at each
successive approximation step is drawn through the V
to meet this current demand is a 0.1 μF capacitor with good high frequency characteristics. This capacitor
is connected between V
Resistance in the path is not recommended because the current will cause a voltage drop which could
result in conversion errors. Inductance in this path must be minimum (parasitic only).
Freescale Semiconductor
REFH
REFH
DD
SS
DDA
. If externally available, connect the V
. If externally available, connect the V
is the power supply for setting the high-reference voltage for the converter. In some packages,
is connected internally to V
potential (V
DDA
If externally available, route V
and place bypass capacitors as near as possible to the package.
Route V
capacitors as near as possible to the package.
, or may be driven by an external source that is between the minimum V
REFH
REFH
REFH
must never exceed V
carefully for maximum noise immunity and place bypass
and V
SSA
MC68HC08QY/QT Family Data Sheet, Rev. 2
SSA
DDA
DDA
REFL
DDA
pin makes a good single point ground location.
. If externally available, V
as its ground pin. In some packages, V
as its power pin. In some packages, V
DDA
and must be placed as close as possible to the package pins.
for good results.
SSA
SSA
DDA
SSA
)
DDA
)
pin. This should be the only ground connection between
pin to the same voltage potential as V
DDA
pin to the same voltage potential as V
NOTE
NOTE
carefully for maximum noise immunity
REFH
).
REFH
)
and V
REFH
REFL
DD
and V
may be connected to the same
loop. The best external component
SS
DDA
SSA
as its supply and reference
is connected internally
is connected internally
DD
SS
. External filtering
.
Figure 3-1
DDA
I/O Signals
spec and
for
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