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APPENDIX B LIST OF CAUTIONS
User’s Manual U17894EJ9V0UD
913
(14/35)
Chapter
Cl
assi
fi
cati
on
Function
Details of
Function
Cautions
Page
When rewriting FR2 to FR0, LV1, and LV0 to other than the same data, stop A/D
conversion (ADCS = 0) beforehand.
p.366
The above conversion time does not include clock frequency errors.
Select
conversion time, taking clock frequency errors into consideration.
p.366
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.367
Registers used
by temperature
sensors
Be sure to clear bits 4 to 6 to “0”.
p.367
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.371
<2> can be done between <3> and <4>.
p.371
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.371
Do not change the AVREF0 voltage during <4> to <13>. Although the temperature
sensor detection value does not depend on the AVREF0 voltage and thus there is no
problem even if the AVREF0 voltage varies at every temperature measurement, it must
be stable during a measurement cycle (from <4> to <13>).
p.371
Procedure for
using
temperature
sensors
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. 372
Operating
current in STOP
mode
Shift to STOP mode after clearing the A/D converter (by clearing bit 7 (ADCS) of the
A/D converter mode register (ADM) to 0). The operating current can be reduced by
clearing bit 0 (ADCE) of the A/D converter mode register (ADM) to 0 at the same time.
To restart from the standby status, clear bit 0 (ADIF) of interrupt request flag register
1L (IF1L) to 0 and start operation.
p.375
Soft
Reducing
current when
A/D converter is
stopped
Be sure that the voltage to be applied to AVREF0 normally satisfies the conditions
stated in Table 11-1.
If bit 7 (ADCS) and bit 0 (ADCE) of the A/D converter mode register (ADM) are set to
0, the current will not be increased by the A/D converter even if a voltage is applied to
AVREF0, while the A/D converter is stopped. If a current flows from the power supply
that supplies a voltage to AVREF0 to an external circuit of the microcontroller as shown
in Figure 11-25, AVREF0 = 0 V = AVSS can be achieved and the external current can
be reduced by satisfying the following conditions (see the main text).
p.375
Hard
Input range of
ANI0 to ANI15
Observe the rated range of the ANI0 to ANI15 input voltage. If a voltage of AVREF0 or
higher and AVSS or lower (even in the range of absolute maximum ratings) is input to
an analog input channel, the converted value of that channel becomes undefined. In
addition, the converted values of the other channels may also be affected.
p.376
Conflict between A/D conversion result register (ADCR, ADCRH) write and ADCR or
ADCRH read by instruction upon the end of conversion
ADCR or ADCRH read has priority. After the read operation, the new conversion
result is written to ADCR or ADCRH.
p.376
Chapter
1
Soft
A/D
converter
Conflicting
operations
Conflict between ADCR or ADCRH write and A/D converter mode register (ADM)
write, analog input channel specification register (ADS), or A/D port configuration
register (ADPC) write upon the end of conversion
ADM, ADS, or ADPC write has priority. ADCR or ADCRH write is not performed, nor
is the conversion end interrupt signal (INTAD) generated.
p.376