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APPENDIX B LIST OF CAUTIONS
User’s Manual U17854EJ9V0UD
837
(13/33)
Chapter
Cl
assi
fi
cati
on
Function
Details of
Function
Cautions
Page
Be sure to clear bits 3 to 6 to “0”.
p.310
Set a channel to be used for A/D conversion in the input mode by using port mode
registers 2 (PM2).
p.310
ADS: Analog
input channel
specification
register
Do not set the pin that is set by ADPC as digital I/O by ADS.
p.310
Set a channel to be used for A/D conversion in the input mode by using port mode
registers 2 (PM2).
p.311
Do not set the pin that is set by ADPC as digital I/O by ADS.
p.311
When using all ANI0/P20 to ANI7/P27 pins as digital I/O (D), the setting can be done
by ADPC4 to ADPC0 = either 01000 or 10000.
p.311
ADPC: A/D port
configuration
register
P20/ANI0 to P27/ANI7 are set as analog inputs in the order of P27/ANI7, …,
P20/ANI0 by the A/D port configuration register (ADPC). When using P20/ANI0 to
P27/ANI7 as analog inputs, start designing from P27/ANI7.
p.311
PM2: Port mode
registers 2
If a pin is set as an analog input port, not the pin level but “0” is always read.
p.312
Basic operations
of A/D converter
Make sure the period of <2> to <6> is 1
μs or more.
p.313
Make sure the period of <2> to <6> is 1
μs or more.
p.317
<2> may be done between <3> and <5>.
p.317
A/D conversion
operation
The period from <7> to <10> differs from the conversion time set using bits 5 to 1
(FR2 to FR0, LV1, LV0) of ADM. The period from <9> to <10> is the conversion time
set using FR2 to FR0, LV1, and LV0.
p.317
Temperature
sensor function
The temperature sensor cannot be used when low current consumption mode is set
(RMC = 5AH) or when the internal high-speed oscillator has been stopped
(HIOSTOP = 1 (bit 0 of CSC register)). The temperature sensor can operate as long
as the internal high-speed oscillator operates (HIOSTOP = 0), even if it is not
selected as the CPU/peripheral hardware clock source.
p.318
Setting of the A/D port configuration register (ADPC), port mode register 2 (PM2) and
port register 2 (P2) is not required when using the temperature sensor. There is no
problem if the pin function is set as digital I/O.
p.319
Set the conversion times so as to satisfy the following condition. fAD = 0.6 to 1.8 MHz p.319
When rewriting FR2 to FR0, LV1, and LV0 to other than the same data, stop A/D
conversion (ADCS = 0) beforehand.
p.319
The above conversion time does not include clock frequency errors.
Select
conversion time, taking clock frequency errors into consideration.
p.319
When using a temperature sensor, use the result of the second or later A/D
conversion for temperature sensor 0 (ANI0 side), and the result of the third or later
A/D conversion for temperature sensor 1 (ANI1 side).
p.320
Registers used
by temperature
sensors
Be sure to clear bits 4 to 6 to “0”.
p.320
Make sure the period of <2> to <5> is 1
μs or more. If ADCS is set to 1 within 1 μs,
the result of the third and later conversion becomes valid on the sensor 0 side.
p.324
<2> can be done between <3> and <4>.
p.324
The period from <7> to <10> differs from the conversion time set using bits 5 to 1
(FR2 to FR0, LV1, LV0) of ADM. The period from <9> to <10> is the conversion time
set using FR2 to FR0, LV1, and LV0.
p.324
Chapter
1
0
Soft
A/D
converter
Procedure for
using
temperature
sensors
Do not change the AVREF voltage during <4> to <13>.
Although the temperature
sensor detection value does not depend on the AVREF voltage and thus there is no
problem even if the AVREF voltage varies at every temperature measurement, it must
be stable during a measurement cycle (from <4> to <13>).
p.324