UPD784938 Datasheet, PDF (418/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 16 A/D CONVERTER
16.4.4 A/D conversion operation start by software
An A/D conversion operation start by software is performed by writing a value to the A/D converter mode register (ADM)
that sets the TRG bit of the ADM register to 0 and the CS bit to 1.
If a value is written to the ADM during an A/D conversion operation (CS bit = 1) such that the TRG bit is set to 0 and
the CS bit to 1 again, the A/D conversion operation being performed at that time is suspended, and A/D conversion is started
immediately in accordance with the written value.
Once A/D conversion operation is started, as soon as one A/D conversion operation ends the next A/D conversion
operation is started in accordance with the operation mode set by the ADM, and conversion operations continue repeatedly
until an instruction that writes to the ADM is executed.
When A/D conversion operation is started by software (TRG bit = 0), INTP5 pin (P26 pin) input does not affect the A/D
conversion operation.
(1) Select mode A/D conversion operation
An A/D conversion operation is started on the analog input pin set by the A/D converter mode register (ADM). As soon
as the A/D conversion operation ends, another A/D conversion operation is performed on the same analog input pin.
An A/D conversion end interrupt request (INTAD) is generated at the end of each A/D conversion operation.
Figure 16-11. Software Start Select Mode A/D Conversion Operation
A/D conversion
ANIn
Conversion start
CS ← 1, TRG ← 0
ANIn
ANIn
ANIm
ADM rewrite
CS ← 1, TRG ← 0
ANIm
ANIm
ADCR
INTAD
Remark n = 0, 1, …, 7
m = 0, 1, …, 7
ANIn
ANIn
ANIm
ANIm
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Preliminary User’s Manual U13987EJ1V0UM00