CHAPTER 13 A/D CONVERTER
User’s Manual U16896EJ2V0UD
369
ADCS
ADCS
0
1
Conversion operation stopped
Conversion operation enabled
Control of A/D conversion operation
ADM
ADMD
FR2
Note 1
FR1
Note 1
FR0
Note 1
ADHS1
Note 1
ADHS0
Note 1
ADCS2
ADMD
0
1
Select mode
Scan mode
Control of operation mode
ADHS1
0
1
Normal mode
High-speed mode (valid only when AV
REF0
≥
4.5 V)
Selection of 5 V A/D conversion time mode (AV
REF0
≥
4.5 V)
ADHS0
0
1
Normal mode
High-speed mode (valid only when AV
REF0
≥
2.7 or 2.85 V)
Selection of 3 V A/D conversion time mode (AV
REF0
≥
2.7 or 2.85 V)
After reset: 00H R/W Address: FFFFF200H
ADCS2
0
1
Reference voltage generator operation stopped
Reference voltage generator operation enabled
Control of reference voltage generator for boosting
Note 2
< >
< >
Notes 1.
For details of the FR2 to FR0 bits and the A/D conversion, refer to
Table 13-2 A/D Conversion
Time
.
2.
The operation of the reference voltage generator for boosting is controlled by the ADCS bit and it
takes 1
μ
s (high-speed mode) or 14
μ
s (normal mode) after operation is started until it is stabilized.
Therefore, the ADCS2 bit is set to 1 (A/D conversion is started) at least 1
μ
s (high-speed mode) or
14
μ
s (normal mode) after if the ADCS2 bit was set to 1 (reference voltage generator for boosting is
on), the first conversion result is valid.
Cautions 1. Writing the ADM register is prohibited during A/D conversion operation (ADCS bit = 1) in
the normal mode (ADHS1, ADHS0 bits = 00).
If the same value is written during A/D conversion operation in the high-speed mode
(ADHS1, ADHS0 bits = 10 or 01), conversion is aborted and started again from the
beginning. Writing the FR2 to FR0, ADHS1, and ADHS0 bits is prohibited during A/D
conversion operation.
2. Setting ADHS1 and ADHS0 bits to 11 is prohibited.
3. Accessing the ADM register is prohibited in the following statuses. For details, refer to
3.4.8 (1) (b) Access to special on-chip peripheral I/O register.
•
When the CPU operates on the subclock and the main clock oscillation is stopped
•
When the CPU operates on the internal oscillation clock
Remark
f
XX
: Main clock frequency
<R>
<R>