
CHAPTER 9 A/D CONVERTER
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9.8 Precautions in Use of A/D Converter
(1) When A/D converter is set in the timer trigger mode
The coincidence interrupt of the compare register becomes the A/D conversion start trigger and conversion
operations are started. At this time, the coincidence interrupt of the compare register also functions as the
coincidence interrupt of the compare register for the CPU. To prevent generation of the coincidence interrupt
of the compare register for the CPU, disable interrupt using the interrupt mask bit (P11MK0 to P11MK3) of
the interrupt control register (P11IC0 to P11IC3).
(2) When A/D converter is set in the external trigger mode
The external trigger input becomes the A/D conversion start trigger and conversion operations are started.
At this time, the external trigger input also functions as a capture trigger and the external interrupt of timer
1. To prevent capture trigger and external interrupt from generating, set timer 1 to the compare register and
disable the interrupt with the interrupt mask bit of the interrupt control register.
The operations performed when timer 1 is set to the compare register and interrupt is not disabled by the
interrupt control register are as follows.
(a) When the interrupt mask bit (IMS113) of the TUM11 register is 0
Functions as the coincidence interrupt of the compare register for the CPU.
(b) When the interrupt mask bit (IMS113) of the TUM11 register is 1
The external trigger input of the A/D converter functions as the external interrupt for the CPU.
Figure 9-17. Relation between A/D Converter, Ports, INTC, and RPU
PORT
RPU
PMC0 register
PMC07
TUM11 register
CMS113
Capture
trigger
Capture
Compare
TUM11 register
IMS113
A/D
Timer trigger
External trigger
Timer/external
interrupt request
INTM1 register
ES031, ES030
P11IC3 register
P11MK3
Interrupt
control
Interrupt
enable/disable
Trigger
ADM1 register
TRG2 to TRG0
Noise
elimination
Edge
selection
P07/INTP113/
ADTRG
External interrupt request
Timer interrupt request
INTC