UPD784938 Datasheet, PDF (416/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 16 A/D CONVERTER
16.4.3 Scan mode
Two scan modes, 1 and 0, are available. In scan mode 0, delay control that takes delay in reading the A/D conversion
result by the CPU into consideration can be performed. In scan mode 1, no delay control is performed but the A/D conversion
interval is fixed.
Generally, use of scan mode 1 is recommended.
(1) Scan mode 0 (bit 5 (SCMD) of A/D converter mode register (ADM) = 0)
Input from the analog input pins specified by bits 1 to 3 (ANIS0 to ANIS2) of the ADM is selected and converted in
order.
For example, if ANIS2 to ANIS0 of the ADM = 001, ANI0 and ANI1 will be scanned repeatedly (ANI0 → ANI1 → ANI0
→ ANI1 → ...). In the scan mode, at the end of the conversion operation for each input the conversion value is stored
in the A/D conversion result register (ADCR) and an A/D conversion end interrupt request (INTAD) is generated.
Figure 16-9. Scan Mode 0 Operation Timing
(a) TRG bit ← 0
A/D conversion
ANI0
ANI1
ANI0
ANI1
ANI0
ANI1
Conversion start Conversion end Conversion end
( CS ← 1
MS ← 0
ANIS2 to ANIS0 ← 001
Conversion end
Conversion end
Conversion end
Conversion end
ADCR
ANI0
ANI1
ANI0
ANI1
ANI0
INTAD
(b) TRG bit ← 1
INTP5
Initialization
A/D conversion
ANI0
Initialization Initialization
ANI1 ANI2 ANI0
ANI0
Initialization
ANI1
ANI0
Conversion start Conversion end Conversion end
( CS ← 1
MS ← 1
ANIS2 to ANIS0 ← 010
Conversion end
Conversion end
ADCR
ANI0
ANI1
ANI0
INTAD
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Preliminary User’s Manual U13987EJ1V0UM00