Power-Fail Compare Mode - NEC V850ES/F 3-L Series User Manual

32-bit single-chip microcontroller

Table of Contents

19.4.4 Power-fail compare mode

Conversion start

Set ADA0CE bit = 1

The A/D conversion end interrupt request signal (INTAD) can be controlled as

follows by the ADAnPFM and ADAnPFT registers.

• When the ADAnPFE bit = 0, the INTAD signal is generated each time

conversion is completed (normal use of the A/D Converter).

• When the ADAnPFE bit = 1 and when the ADAnPFC bit = 0, the value of the

ADAnCRmH register is compared with the value of the ADAnPFT register

when conversion is completed, and the INTAD signal is generated only if

ADAnCR0H ≥ ADAnPFT.

• When the ADAnPFE bit = 1 and when the ADAnPFC bit = 1, the value of the

ADAnCRmH register is compared with the value of the ADAnPFT register

when conversion is completed, and the INTAD signal is generated only if

ADAnCR0H < ADAnPFT.

In the power-fail compare mode, four modes are available as modes in which

to set the ANInm pins: continuous select mode and continuous scan mode,

one-shot select mode and one-shot scan mode.

Continuous select mode

In this mode, the result of converting the voltage of the analog input pin

specified by the ADAnS register is compared with the set value of the

ADAnPFT register. If the result of power-fail comparison matches the condition

set by the ADAnPFC bit, the conversion result is stored in the ADAnCRm

conversion result is stored in the ADAnCRm register, and the INTAD signal is

not generated. After completion of the first conversion, the next conversion is

started, unless the ADAnCE bit of the ADAnM0 register is cleared to 0.

Timing example of continuous select mode operation

(when power-fail comparison is made: ADA0S register = 01H)

User's Manual U18743EE1V2UM00

A/D Converter (ADC)

Conversion start

Set ADA0CE bit = 1