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12.3 A/D Converter Control Registers
The following four types of registers are used to control A/D converter.
• A/D converter mode register (ADM1)
• Analog input channel specification register (ADS1)
• Power-fail compare mode register (PFM)
• Power-fail compare threshold value register (PFT)
(1) A/D converter mode register (ADM1)
This register sets the conversion time for analog input to be A/D converted, conversion start/stop and external
trigger.
ADM1 is set with an 8-bit memory manipulation instruction.
RESET input clears ADM1 to 00H.
Figure 12-3. A/D Converter Mode Register (ADM1) Format
Address: FF80H After Reset: 00H R/W
Symbol
7
ADM1
ADCS1
ADCS1
0
1
FR12
0
0
0
1
1
1
Other than above
Notes 1. Set so that the A/D conversion time is 14 µ s or more.
2. Setting prohibited because the A/D conversion time will be less than 14 µ s.
Cautions 1. Bits 0 to 2 and 6 must be set to 0.
2. When rewriting FR10 to FR12 to other data, stop the A/D conversion operation beforehand.
Remarks 1. f
: Main system clock oscillation frequency
X
2. Figures in parentheses apply to operation with f
CHAPTER 12 A/D CONVERTER
6
5
0
FR12
FR11
A/D Conversion Operation Control
Conversion operation stop.
Conversion operation enabled.
FR11
FR10
0
0
144/f
0
1
120/f
1
0
96/f
X
0
0
288/f
0
1
240/f
1
0
192/f
Setting prohibited
Preliminary User's Manual U14581EJ3V0UM00
4
3
2
FR10
0
Conversion Time Selection
(17.2 µ s)
X
(14.3 µ s)
X
(Note 2)
(34.4 µ s)
X
(28.6 µ s)
X
(22.9 µ s)
X
= 8.38 MHz.
X
1
0
0
0
Note 1
157
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