upd70f3402 Renesas Electronics Corporation., upd70f3402 Datasheet - Page 395

• Manufacturer Part Number: upd70f3402
• Description: 32-/16-bit Single-chip Microcontroller With Can Interface
• Manufacturer: Renesas Electronics Corporation.

11.7 Cautions
(1)
(2)
(3)
(4)
When A/D converter is not used
When the A/D converter is not used, the power consumption can be reduced by clearing the CE
bit of the ADSCM0H register and PDB bit of the ADSCM1H register to 0.
Input range of ANI0 to ANI15 pins
Input the voltage within the specified range to the ANI0 to ANI15 pins. If a voltage equal to or
higher than AV
maximum ratings) is input to any of these pins, the conversion value of that channel is undefined,
and the conversion value of the other channels may also be affected.
Countermeasures against noise
To maintain the 10-bit resolution, the ANI0 to ANI15 pins must be effectively protected from noise.
The influence of noise increases as the output impedance of the analog input source becomes
higher. To lower the noise, connecting an external capacitor as shown in Figure 11-16 is
recommended.
Alternate I/O
The analog input pins (ANI0 to ANI15) function alternately as port pins. When selecting one of the
ANI0 to ANI15 pins to execute A/D conversion, do not execute an instruction to read an input port
or write to an output port during conversion as the conversion resolution may drop.
If a digital pulse is applied to a pin adjacent to the pin whose input signal is being converted, the
A/D conversion value may not be as expected due to the influence of coupling noise. Therefore, do
not apply a pulse to a pin adjacent to the pin undergoing A/D conversion.
REF0
or equal to or lower than AV
Figure 11-16: Processing of Analog Input Pin
User’s Manual U16702EE3V2UD00
Chapter 11 A/D Converter
Clamp with a diode with a low V (0.3 V or less)
if noise equal to or higher then AV
or lower than AV
AV
V
AV
GND0
DD
REF0
SS
SS
(even within the range of the absolute
SS
may be generated.
F
DD
or equal to
395