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R01UH0336EJ0102 Rev.1.02
Page 1311 of 1538
Jul 17, 2014
V850E2/PG4-L
Section 23 A/D Converter
23.3.14
Buffer Amplifier Function
If required, the analogue input signal can be connected to an internal buffer
amplifier. Charging the internal sampling capacitor is accelerated by the buffer
amplifier during sampling in A/D conversion.
The buffer amplifier function is enabled by setting ADCAnCTL1.ADCAnBPC to
1.
The buffer amplifier function is not available while a channel’s sample-and-hold
function is in use.
Figure 23-20
A/D Conversion Timing when Buffer Amplifier Function is Enabled
Caution
In the channel with the channel S/H function enabled, the conversion is
performed with the buffer amplifier function automatically being disabled.
23.3.15
Stabilization Control
The A/D converter needs time to stabilize operation at power on of the A/D
converter (ADCAnCTL1.ADCAnGPS = 1).
Although a start trigger is acceptable even during the stabilization time, A/D
conversion is not started before the stabilization time has elapsed.
In order to secure the minimum stabilization time, the setting of the stabilization
time counter ADCAnCNT must be adapted. Refer to Section 23.4.2 (5),
ADCAnCNT – A/D Converter Stabilization Counter for details.
Sampling
Buffer
amplifier
Buffer
amplifier
Sampling
A/D Conversion
Total conversion time