NEC 78K0S/KA1+ Preliminary User's Manual page 158

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(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 input clears this register to 00H.
Address: FF80H
Symbol <7>
ADM ADCS
ADCS
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FR2
ADCE
Notes
158
CHAPTER 10 A/D CONVERTER
Figure 10-4. Format of A/D Converter Mode Register (ADM)
After reset: 00H R/W
6 5
0 FR2
0 Stops conversion operation
1 Enables conversion operation
FR1 FR0
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
0 Stops operation of reference voltage generator
1 Enables operation of reference voltage generator
1. Set the sampling time as follows.
• AV ≥ 4.5 V:
1.0
REF
• AV ≥ 4.0 V:
2.4
REF
• AV ≥ 2.85 V: 3.0
REF
• AV ≥ 2.7 V:
11.0
REF
2. Set the A/D conversion time as follows.
• AV ≥ 4.5 V:
3.0
REF
• AV ≥ 4.0 V:
4.8
REF
• AV ≥ 2.85 V: 6.0
REF
• AV ≥ 2.7 V:
14.0
REF
3. A booster circuit is incorporated to realize low-voltage operation. The operation of the circuit that
generates the reference voltage for boosting is controlled by ADCE, and it takes 1
operation start to operation stabilization. Therefore, when ADCS is set to 1 after 1
has elapsed from the time ADCE is set to 1, the conversion result at that time has priority over
the first conversion result.
Preliminary User's Manual U16898EJ1V0UD
4 3
FR1 FR0
A/D conversion operation control
Sampling Conversion
Note 1 Note 2
Time Time
12/f 36/f 1.5
XP XP
24/f 48/f 3.0
XP XP
48/f 72/f 6.0
XP XP
88/f 112/f 11.0
XP XP
24/f 72/f 3.0
XP XP
48/f 96/f 6.0
XP XP
96/f 144/f 12.0
XP XP
176/f 224/f 22.0
XP XP
Boost reference voltage generator operation control
µ
s or more
µ
s or more
µ
s or more
µ
s or more
µ
s or more and less than 100
µ
s or more and less than 100
µ
s or more and less than 100
µ
s or more and less than 100
2 1
0 0
f = 8 MHz f
XP XP
Sampling Conversion Sampling
Note 1 Note 2 Note 1
Time Time Time
µ µ µ
s 4.5 s 1.2 s
µ µ µ
s 6.0 s 2.4 s
µ µ µ
s 9.0 s 4.8 s
µ µ µ
s 14.0 s 8.8 s
µ µ µ
s 9.0 s 2.4 s
µ µ µ
s 12.0 s 4.8 s
µ µ µ
s 18.0 s 9.6 s
µ µ µ
s 28.0 s 17.2 s
Note 3
µ
s
µ
s
µ
s
µ
s
<0>
ADCE
= 10 MHz
Conversion
Note 2
Time
µ
3.6 s
µ
4.8 s
µ
7.2 s
µ
11.2 s
µ
7.2 s
µ
9.6 s
µ
14.4 s
µ
22.4 s
µ
s from
µ
s or more