NEC V850ES/KE1+ User Manual page 371

(a) Controlling reference voltage generator for boosting
When the ADCS2 bit = 0, power to the A/D converter drops. The converter requires a setup time of 1
(high-speed mode) or 14
Therefore, the result of A/D conversion becomes valid from the first result by setting the ADCS bit to 1 at
μ
least 1 s (high-speed mode) or 14
ADCS ADCS2
0 0 Stopped status (DC power consumption path does not exist)
0 1 Conversion standby mode (only the reference voltage generator for boosting consumes power)
1 0 Conversion mode (reference voltage generator stops operation
1 1 Conversion mode (reference voltage generator is operating
Notes 1. If the ADCS and ADCS2 bits are changed from 00B to 10B, the reference voltage generator for
boosting automatically turns on. If the ADCS bit is cleared to 0 while the ADCS2 bit is 0, the voltage
generator automatically turns off. In the software trigger mode (ADS.TRG bit = 0), use of the first A/D
conversion result is prohibited.
In the hardware trigger mode (TRG bit = 1), use the A/D conversion result only if A/D conversion is
started after the lapse of the oscillation stabilization time of the reference voltage generator for
boosting.
2. If the ADCS and ADCS2 bits are changed from 00B to 11B, the reference voltage generator for
boosting automatically turns on. If the ADCS bit is cleared to 0 while the ADCS2 bit is 1, the voltage
generator stays on. In the software trigger mode (TRG bit = 0), use of the first A/D conversion result is
prohibited.
In the hardware trigger mode (TRG bit = 1), use the A/D conversion result only if A/D conversion is
started after the lapse of the oscillation stabilization time of the reference voltage generator for
boosting.
ADCS2
Comparator control
ADCS
μ
Note 1 s (high-speed mode) or 14
voltage generator for boosting between when the ADCS2 bit is set (1) and when the ADCS bit is set (1).
CHAPTER 13 A/D CONVERTER
μ
s (normal mode) or more after the ADCS2 bit has been set to 1.
μ
s (normal mode) after the ADCS2 bit has been set to 1.
Table 13-3. Setting of ADCS Bit and ADCS2 Bit
A/D Conversion Operation
Figure 13-2. Operation Sequence
Reference voltage generator for boosting: Operating
Conversion
operation
Note
μ
s (normal mode) or more are required for the operation of the reference
User's Manual U16896EJ2V0UD
Note 1
)
Note 2
)
Conversion Conversion
standby operation
μ
s
Conversion
stop
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