M306H7MG-XXXFP Datasheet, PDF (178/329 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with DATA ACQUISITION CONTROLLER

M306H7MG-XXXFP/MC-XXXFP/FGFP
12. A/D CONVERTER
12.9 Current Consumption Reducing Function
When not using the A/D converter, its resistor ladder and reference voltage input pin (VREF) can be separated using
the ADCON1 register’s VCUT bit. When separated, no current will flow from the VREF pin into the resistor ladder,
helping to reduce the power consumption of the chip.
To use the A/D converter, set the VCUT bit to “1” (VREF connected) and then set the ADCON0 register’s ADST bit
to “1” (A/D conversion start). The VCUT and ADST bits cannot be set to “1” at the same time.
Nor can the VCUT bit be set to “0” (VREF unconnected) during A/D conversion.
12.10 Analog Input Pin and External Sensor Equivalent Circuit Example
Figure 12.10 shows analog input pin and external sensor equivalent circuit example.
Sensor equivalent
circuit
R0
VIN
Microcomputer
R
C
Sampling time
VC
Sample-and-hold function enabled:
3
fAD
Sample-and-hold function disabled:
2
fAD
Figure 12.10 Analog Input Pin and External Sensor Equivalent Circuit
Rev.2.10 Oct 25, 2006 Page 178 of 326
REJ03B0152-0210