CHAPTER 13 A/D CONVERTER
647
User’s Manual U14492EJ3V0UD
Figure 13-1. Block Diagram of A/D Converter 0 or 1
ADSCMn0 (16)
15
0
ADTRGn
INTADn
Sample and
hold circuit
ANIn0
ANIn1
ANIn2
ANIn3
ANIn4
ANIn5
ANIn6
ANIn7
ITRG0
16
16
16
16
ADSCMn1 (16)
15
0
ADETM0 (16)
15
0
ADETM1 (16)
15
0
9
0
Trigger source switching
circuit in timer trigger mode
(
Figure 13-2
)
Controller
10
10
SAR (10)
Comparator
and D/A
converter
AV
DD
AV
REFn
AV
SS
INTDETn
ADCRn0
ADCRn1
ADCRn2
ADCRn3
ADCRn4
ADCRn5
ADCRn6
ADCRn7
Internal bus
Input circuit
f
XX
/2
Remark
n = 0, 1
f
XX
: Internal system clock
Cautions 1. Noise at an analog input pin (ANI0n, ANI1n) or reference voltage input pin (AV
REF0
, AV
REF1
) 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.
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.
2. Be sure that voltages outside the range [AV
SS
to AV
REF0
, AV
SS
to AV
REF1
] are not applied to pins
being used as A/D converter 0 and 1 input pins.
Содержание V850E/IA1 mPD703116
Страница 2: ...2 User s Manual U14492EJ3V0UD MEMO...