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(R8C) Are there any hardware precautions for accurate A/D conversion?

Latest Updated:06/19/2006

Question:

Are there any hardware precautions for realizing accurate A/D conversion?

[About the M16C Family products, click here.]

Answer:

In order to perform A/D conversion, it is necessary to fully charge the internal capacitor, but if the impedance of the A/D conversion target is high, the discharge and charge will take time and the conversion value will not be accurate. For correct A/D conversion, please set the impedance of the signal source connected to the analog input pin so that it is low enough. (Refer to the hardware manual for the calculation method.) Moreover, in order to suppress the influence of the input current at the time of A/D conversion, please add a capacitor to the analog input pin.

Example (R8C/25)

Suitable Products
R8C/18
R8C/19
R8C/1A
R8C/1B
R8C/20
R8C/21
R8C/22
R8C/23
R8C/24
R8C/25
R8C/26
R8C/27
R8C/28
R8C/29
R8C/2A
R8C/2B
R8C/2C
R8C/2D
R8C/2E
R8C/2F
R8C/2G
R8C/2H
R8C/2J
R8C/2K
R8C/2L
R8C/32C
R8C/33C
R8C/34C
R8C/35C
R8C/36C
R8C/38C
R8C/3GC
R8C/3JC
R8C/32D
R8C/33D
R8C/35D
R8C/3GD
R8C/33T
R8C/38A
R8C/34E, R8C/34F, R8C/34G, R8C/34H
R8C/36E, R8C/36F, R8C/36G, R8C/36H
R8C/38E, R8C/38F, R8C/38G, R8C/38H
R8C/L35C
R8C/L36C
R8C/L38C
R8C/L3AC