Operation In A/D Trigger Polling Mode; Operation In Select Mode - NEC UPD703116 User Manual

13.7 Operation in A/D Trigger Polling Mode

Setting the ADCE0 or ADCE1 bit of the ADSCM00 or ADSCM10 register to 1 starts A/D conversion.
Both select mode and scan mode are available in A/D trigger polling mode. Since the ADCS0 or ADCS1 bit of the
ADSCM00 or ADSCM10 register remains 1 after an INTAD0 or INTAD1 interrupt in this mode, it is not necessary to
write 1 in the ADCE0 or ADCE1 bit as an A/D conversion restart operation.

13.7.1 Operation in select mode

The analog input specified in the ADSCM00 or ADSCM10 register is A/D converted. The conversion result is
stored in the ADCR0n or ADCR1n register (n = 0 to 7).
One analog input is A/D converted at a time and the result is stored in one ADCR0n or ADCR1n register. Analog
inputs correspond one-to-one with ADCR0n or ADCR1n register.
An A/D conversion termination interrupt (INTAD0 or INTAD1) is generated for each A/D conversion termination.
A/D conversion operation is repeated until the ADCE0 or ADCE1 bit = 0 (ADCS0 or ADCS1 bit = 1).
Analog Input A/D Conversion Result Register
ANIx ADCRx
Remark x = 00 to 07, 10 to 17
In A/D trigger polling mode, it is not necessary to write 1 in the ADCE0 or ADCE1 bit of the ADSCM00 or
ADSCM10 register as an A/D conversion restart operation
This is optimal for applications that regularly read A/D conversion values.
Note In A/D trigger polling mode, the fact that the ADCE0 or ADCE1 bit of the ADSCM00 or ADSCM10 register
is 0 means that A/D conversion operation does not stop as long as the ADCS0 or ADCS1 bit is not 0.
Therefore, if the ADCR0n or ADCR1n register is not read before the next A/D conversion, it is overwritten.
Figure 13-8. Example of Select Mode (A/D Trigger Polling Select) Operation (ANI02): For A/D Converter 0
ADSCM00
(1) ADCE0 bit of ADSCM00 = 1 (Enabled)
(2) A/D conversion of ANI02
(3) Store conversion result in ADCR02
662
CHAPTER 13 A/D CONVERTER
Note
.
ANI00
ANI01
ANI02
ANI03
A/D converter 0
ANI04
ANI05
ANI06
ANI07
(4) Generate INTAD0 interrupt
(5) Return to (2)
User's Manual U14492EJ5V0UD
ADCR00
ADCR01
ADCR02
ADCR03
ADCR04
ADCR05
ADCR06
ADCR07