UPD78F0411GA-GAM-AX Datasheet, PDF (296/564 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 12 10-BIT SUCCESSIVE APPROXIMATION TYPE A/D CONVERTER (μPD78F041x only)
12.3 Registers Used in 10-Bit Successive Approximation Type A/D Converter
The A/D converter uses the following seven registers.
• A/D converter mode register (ADM)
• A/D port configuration register 0 (ADPC0)
• Analog input channel specification register (ADS)
• Port function register 2 (PF2)
• Port mode register 2 (PM2)
• 10-bit A/D conversion result register (ADCR)
• 8-bit A/D conversion result register (ADCRH)
(1) A/D converter mode register (ADM)
This register sets the conversion time for analog input to be A/D converted, and starts/stops conversion.
ADM can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 12-3. Format of A/D Converter Mode Register (ADM)
Address: FF8DH After reset: 00H R/W
Symbol <7>
6
5
ADM ADCS
FR3^{Note 1}
FR2^{Note 1}
4
FR1^{Note 1}
3
FR0^{Note 1}
2
LV1^{Note 1}
1
LV0^{Note 1}
<0>
ADCE
ADCS
0
1
A/D conversion operation control
Stops conversion operation
Enables conversion operation
ADCE
0
1
Comparator operation control^{Note 2}
Stops comparator operation
Enables comparator operation
Notes 1.
2.
For details of FR3 to FR0, LV1, LV0, and A/D conversion, see Table 12-2 A/D Conversion Time
Selection.
The operation of the comparator is controlled by ADCS and ADCE, and it takes 1 μs from operation
start to operation stabilization. Therefore, when ADCS is set to 1 after 1 μs or more has elapsed from
the time ADCE is set to 1, the conversion result at that time has priority over the first conversion
result. Otherwise, ignore data of the first conversion.
Table 12-1. Settings of ADCS and ADCE
ADCS
ADCE
A/D Conversion Operation
0
0
Stop status (DC power consumption path does not exist)
0
1
Conversion waiting mode (comparator operation, only comparator consumes
power)
1
0
Conversion mode (comparator operation stopped^Note)
1
1
Conversion mode (comparator operation)
Note Ignore data of the first conversion.
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