s908az32ag2cfue Freescale Semiconductor, Inc, s908az32ag2cfue Datasheet - Page 232

• Manufacturer Part Number: s908az32ag2cfue
• Description: M68hc08 Microcontrollers 8-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Analog-To-Digital Converter (ADC-15)
21.6 I/O Signals
The ADC module has 15 channels that are shared with I/O ports B and D. Refer to
Characteristics
21.6.1 ADC Analog Power Pin (V
The ADC analog portion uses V
voltage potential as V
V
21.6.2 ADC Analog Ground Pin (V
The ADC analog portion uses V
as V
V
21.6.3 ADC Voltage In (ADCVIN)
ADCVIN is the input voltage signal from one of the 15 ADC channels to the ADC module.
21.7 I/O Registers
These I/O registers control and monitor ADC operation:
21.7.1 ADC Status and Control Register
The following paragraphs describe the function of the ADC status and control register.
232
REFH
REFL
•
•
•
SS
ADC status and control register (ADSCR)
ADC data register (ADR)
ADC clock register (ADICLK)
is the lower reference supply for the ADC.
.
is the high reference voltage for all analog-to-digital conversions.
Address:
Route V
capacitors as close as possible to the package. V
for operation of the ADC.
for voltages referenced below.
Reset:
Read:
Write:
DD
Figure 21-2. ADC Status and Control Register (ADSCR)
DDAREF
COCO
$0038
Bit 7
. External filtering may be necessary to ensure clean V
R
R
0
= Reserved
carefully for maximum noise immunity and place bypass
SSA
DDAREF
AIEN
6
0
as its ground pin. Connect the V
MC68HC908AZ32A Data Sheet, Rev. 2
DDAREF
as its power pin. Connect the V
SSA
ADCO
5
0
)/ADC Voltage Reference Low Pin (V
)/ADC Voltage Reference Pin (V
NOTE
CH4
4
1
CH3
3
1
DDAREF
SSA
CH2
2
1
DDA
pin to the same voltage potential
must be present
/V
DDAREF
CH1
1
1
DDAREF
Freescale Semiconductor
25.1.6 ADC
REFH
pin to the same
Bit 0
CH0
REFL
for good results.
1
)
)