NEC uPD78056Y User Manual

Page 277

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277

CHAPTER 14 A/D CONVERTER

(2) A/D conversion operation in software start

When bit 6 (TRG) and bit 7 (CS) of A/D converter mode register (ADM) are set to 0 and 1, respectively, the

A/D conversion starts on the voltage applied to the analog input pins specified with bits 1 to 3 (ADM1 to

ADM3) of ADM.

Upon termination of the A/D conversion, the conversion result is stored in the A/D conversion result register

(ADCR) and the interrupt request signal (INTAD) is generated. After one A/D conversion operation is started

and terminated, the next A/D conversion operation starts immediately. The A/D conversion operation

continues repeatedly until new data is written to ADM.

If data with CS set to 1 is written to ADM again during A/D conversion, the converter suspends its A/D

conversion operation and starts A/D conversion on the newly written data.

If data with CS set to 0 is written to ADM during A/D conversion, the A/D conversion operation stops

immediately.

Figure 14-9. A/D Conversion by Software Start

Remarks 1. n = 0, 1, ... , 7

2. m = 0, 1, ... , 7

Conversion Start

CS=1, TRG=0

A /D Conversion

ADCR

INTAD

ANIn

ANIn

ANIm

ANIn

ANIm

ANIm

ANIn

ANIn

ADM Rewrite

CS=1, TRG=0

ADM Rewrite

CS=0, TRG=0

Conversion suspended
Conversion results are
not stored

Stop

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