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CHAPTER 9 A/D CONVERTER
(2) 4-buffer mode operations (Timer trigger select: 4-buffer)
A/D conversion of one analog input is executed four times, and the results are stored in the ADCRn register.
There are two 4-buffer modes, 1-trigger mode and 4-trigger mode, according to the number of triggers.
This mode is suitable for applications which calculate the average of the A/D conversion result.
(a) 1-trigger mode (Timer trigger select: 4-buffer, 1-trigger)
A/D converts one analog input four times using the coincidence interrupt signal (INTCC110) as a trigger,
and stores the results in four ADCRn registers.
Generates an INTAD interrupt when the four A/D conversions end and ends the A/D conversion.
When the TM11 is set to the one-shot mode, and less than four coincidence interrupts are generated,
if the CE bit is set to 1, the INTAD interrupt is not generated and the standby state is set.
Figure 9-10. 1-Trigger Mode (Timer Trigger Select 4-Buffer 1-Trigger) Operation
ANI0
ANI1
ANI2
ANI3
ANI4
ANI5
ANI6
ANI7
ADCR0
ADCR1
ADCR2
ADCR3
ADCR4
ADCR5
ADCR6
ADCR7
A/D Converter
INTCC110
(
×
4)
(
×
4)
Caution Analog inputs enclosed by dotted line are not available.
(b) 4-trigger mode (Timer trigger select: 4-buffer, 4-trigger)
A/D converts one analog input four times using four coincidence interrupt signals (INTCC110 to
INTCC113) as triggers and stores the results in four ADCRn registers. The INTAD interrupt is generated
when the four A/D conversions end, the CS bit is reset (0), and A/D conversion ends.
When the TM11 is set to the one-shot mode, A/D conversion is ended in four conversions. To restart
the A/D conversion, input the valid edge to the TCLR11 pin or write 1 to the CE11 bit of the TMC11 register
to restart the TM11. When the first coincidence interrupt after TM11 is restarted is generated, the CS
bit is set (1) and A/D conversion is started.
When set to the loop mode, unless the CE bit is set to 0, A/D conversion is repeated each time the
coincidence interrupt is generated.
The coincidence interrupts (INTCC110 to INTCC113) can be generated in any order. The conversion
result is stored in the ADCRn register corresponding to the input trigger. The same trigger, even when
it enters several times consecutively, is accepted as a trigger each time.