NEC 78K0R/KE3 User Manual page 304

16-bit single-chip microcontrollers

Table of Contents

(2) A/D converter mode register (ADM)

This register sets the conversion time for analog input to be A/D converted, and starts/stops conversion.

ADM can be set by a 1-bit or 8-bit memory manipulation instruction.

Reset signal generation clears this register to 00H.

Address: FFF30H

For details of FR2 to FR0, LV1, LV0, and A/D conversion, see Table 10-3 A/D Conversion Time

The operation of the A/D voltage comparator is controlled by ADCS and ADCE, and it takes 1

operation start to operation stabilization. Therefore, when ADCS is set to 1 after 1

elapsed from the time ADCE is set to 1, the conversion result at that time has priority over the first

conversion result. Otherwise, ignore data of the first conversion.

Note To stabilize the internal circuit, the time from the rising of the ADCE bit to the falling of the ADCS bit must be

s or longer.

Caution A/D conversion must be stopped before rewriting bits FR0 to FR2, LV1, and LV0 to values other

than the identical data.

CHAPTER 10 A/D CONVERTER

Figure 10-4. Format of A/D Converter Mode Register (ADM)

After reset: 00H

Stops conversion operation

Enables conversion operation

Stops A/D voltage comparator operation

Enables A/D voltage comparator operation

Table 10-2. Settings of ADCS and ADCE

Stop status (DC power consumption path does not exist)

Conversion waiting mode (only A/D voltage comparator consumes power)

Setting prohibited

Conversion mode (A/D voltage comparator: enables operation)

Figure 10-5. Timing Chart When A/D voltage Comparator Is Used

A/D voltage comparator : enables operation

User's Manual U17854EJ9V0UD

A/D conversion operation control

A/D voltage comparator operation control

A/D Conversion Operation

s or more has