526
Chapter 15
A/D Converter
Preliminary User’s Manual U15839EE1V0UM00
Figure 15-1:
Block Diagram of A/D Converter
Cautions: 1. Noise at an analog input pin (ANIm) or reference voltage input pin (AV
REF
) may
give rise to an invalid conversion result.
Software processing is needed in order to prevent this invalid conversion result
from adversely affecting the system.
2. The following are examples of software processing:
•
Use the average value of the results of multiple A/D conversions as the A/D
conversion result.
•
Perform A/D conversion multiple consecutive times and use conversion
results with the exception of any abnormal conversion results that are
obtained.
•
If an A/D conversion result from which it is judged that an abnormality
occurred in the system is obtained, do not perform abnormality processing at
once but perform it upon reconfirming the occurrence of an abnormality.
3. Be sure that voltages outside the range [AV
SS
to AV
REF
] are not applied to pins
being used as A/D converter and input pins.
ANI5
ANI6
ANI7
ANI8
Selector
Sample & hold circuit
ANI9
ANI10
ANI11
Internal Bus
ANI0
ANI1
ANI2
ANI3
ANI4
Input Circuit
AV
DD
AV
REF
AV
SS
Successive
approximation
register SAR
Comparator
and D/A
Converter
Controller
ADCRH
ADCR
15
8 7
0
10
16
8
4
ADS3 ADS2 ADS1 ADS0
4
ADCS
0
FR3
FR2
FR1
FR0
0
8
8
INTAD
Analog input channel
setting register (ADS)
A/D converter mode
register (ADM)
A/D conversion result
registers (ADCRL/ADCRH)
ADCRL
Summary of Contents for mPD703128
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