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APPENDIX B LIST OF CAUTIONS
User’s Manual U17894EJ9V0UD
912
(13/35)
Chapter
Cl
assi
fi
cati
on
Function
Details of
Function
Cautions
Page
Set the conversion times with the following conditions.
4.0 V
≤ AVREF0 ≤ 5.5 V: fAD = 0.6 to 3.6 MHz
2.7 V
≤ AVREF0 < 4.0 V: fAD = 0.6 to 1.8 MHz
2.3 V
≤ AVREF0 < 2.7 V: fAD = 0.6 to 1.44 MHz
p.354
When rewriting FR2 to FR0, LV1, and LV0 to other than the same data, stop A/D
conversion once (ADCS = 0) beforehand.
p.354
Change LV1 and LV0 from the default value, when 2.3 V
≤ AVREF0 < 2.7 V.
p.354
A/D conversion
time selection
(2.3 V
≤ AVREF0 ≤
5.5 V)
The above conversion time does not include clock frequency errors.
Select
conversion time, taking clock frequency errors into consideration.
p.354
ADCR: 10-bit
A/D conversion
result register
When writing to the A/D converter mode register (ADM), analog input channel
specification register (ADS), and A/D port configuration register (ADPC), the contents
of ADCR may become undefined. Read the conversion result following conversion
completion before writing to ADM, ADS, and ADPC.
Using timing other than the
above may cause an incorrect conversion result to be read.
p.356
ADCRH: 8-bit
A/D conversion
result register
When writing to the A/D converter mode register (ADM), analog input channel
specification register (ADS), and A/D port configuration register (ADPC), the contents
of ADCRH may become undefined. Read the conversion result following conversion
completion before writing to ADM, ADS, and ADPC.
Using timing other than the
above may cause an incorrect conversion result to be read.
p.356
Be sure to clear bits 4 to 6 to “0”.
p.357
Set a channel to be used for A/D conversion in the input mode by using port mode
registers 2 and 15 (PM2, PM15).
p.357
ADS: Analog
input channel
specification
register
Do not set the pin that is set by ADPC as digital I/O by ADS.
p.357
Set a channel to be used for A/D conversion in the input mode by using port mode
registers 2 and 15 (PM2, PM15).
p.358
Do not set the pin that is set by ADPC as digital I/O by ADS.
p.358
ADPC: A/D port
configuration
register
P20/ANI0 to P27/ANI7 and P150/ANI8 to P157/ANI15 are set as analog inputs in the
order of P157/ANI15, …, P150/ANI8, P27/ANI7, …, P20/ANI0 by the A/D port
configuration register (ADPC). When using P20/ANI0 to P27/ANI7 and P150/ANI8 to
P157/ANI15 as analog inputs, start designing from P157/ANI15.
p.358
PM2, PM15: Port
mode registers 2
and 15
If a pin is set as an analog input port, not the pin level but “0” is always read.
p.359
Basic operations
of A/D converter
Make sure the period of <2> to <6> is 1
μs or more.
p.360
Make sure the period of <2> to <6> is 1
μs or more.
p.364
<2> may be done between <3> and <5>.
p.364
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.364
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.365
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.366
Chapter
1
Soft
A/D
converter
Registers used
by temperature
sensors
Set the conversion times so as to satisfy the following condition. fAD = 0.6 to 1.8 MHz p.366