mc908jl16 Freescale Semiconductor, Inc, mc908jl16 Datasheet - Page 131

• Manufacturer Part Number: mc908jl16
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

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).
9.7.4 ADC10 Voltage Reference Low Pin (V
V
V
potential as V
charging. If externally available, connect the V
ground location.
9.7.5 ADC10 Channel Pins (ADn)
The ADC10 has multiple input channels. Empirical data shows that capacitors on the analog inputs
improve performance in the presence of noise or when the source impedance is high. 0.01 µF capacitors
with good high-frequency characteristics are sufficient. These capacitors are not necessary in all cases,
but when used they must be placed as close as possible to the package pins and be referenced to V
9.8 Registers
These registers control and monitor operation of the ADC10:
9.8.1 ADC10 Status and Control Register
This section describes the function of the ADC10 status and control register (ADCSC). Writing ADCSC
aborts the current conversion and initiates a new conversion (if the ADCH[4:0] bits are equal to a value
other than all 1s).
Freescale Semiconductor
REFL
REFL
•
•
•
ADC10 status and control register, ADCSC
ADC10 data registers, ADRH and ADRL
ADC10 clock register, ADCLK
is the power supply for setting the low-reference voltage for the converter. In some packages,
is connected internally to V
SSA
Address:
Route V
capacitors as near as possible to the package.
Reset:
Read:
Write:
. There will be a brief current associated with V
Figure 9-3. ADC10 Status and Control Register (ADCSC)
REFH
$003C
COCO
Bit 7
REFH
0
carefully for maximum noise immunity and place bypass
and V
= Unimplemented
AIEN
SSA
6
0
REFL
MC68HC908JL16 Data Sheet, Rev. 1.1
. If externally available, connect the V
and must be placed as close as possible to the package pins.
ADCO
5
0
REFL
NOTE
ADCH4
REFL
pin to the same potential as V
4
1
REFH
)
and V
ADCH3
3
1
REFL
REFL
ADCH2
loop. The best external component
2
1
when the sampling capacitor is
REFL
ADCH1
1
1
pin to the same voltage
SSA
ADCH0
at the single point
Bit 0
1
Registers
SSA
131
.