Datasheet

78K0/Kx2-L CHAPTER 12 A/D CONVERTER
R01UH0028EJ0400 Rev.4.00 405
Sep 27, 2010
12.3 Registers Used in A/D Converter
The A/D converter uses the following seven registers.
• A/D converter mode register 0 (ADM0)
• 10-bit A/D conversion result register (ADCR)
• 8-bit A/D conversion result register L (ADCRL)
• 8-bit A/D conversion result register H (ADCRH)
• Analog input channel specification register (ADS)
• A/D port configuration registers 0, 1 (ADPC0, ADPC1)
• Port mode registers 1, 2, 7 (PM1, PM2, PM7)
(1) A/D converter mode register 0 (ADM0)
This register sets the conversion time for analog input to be A/D converted, and starts/stops conversion.
ADM0 can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 12-2. Format of A/D Converter Mode Register 0 (ADM0)
ADCELV0
Note 1
LV1
Note 1
FR0
Note 1
FR1
Note 1
FR2
Note 1
0ADCS
A/D conversion operation control
Stops conversion operation
Enables conversion operation
ADCS
0
1
<0>123456<7>
ADM0
Address: FF28H After reset: 00H R/W
Symbol
A/D voltage comparator operation control
Note 2
Stops A/D voltage comparator operation
Enables A/D voltage comparator operation
ADCE
0
1
Notes 1. For details of FR2 to FR0, LV1, LV0, and A/D conversion, refer to Table 12-2 A/D Conversion Time
Selection.
2. The operation of the A/D voltage comparator is controlled by ADCS and ADCE, and it takes 1
μ s from
operation start to operation stabilization. Therefore, when ADCS is set to 1 after 1 μ s 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 (only A/D voltage comparator consumes power)
1 0 Setting prohibited
1 1 Conversion mode (A/D voltage comparator operation)