Datasheet
78K0/Ix2 CHAPTER 11 A/D CONVERTER
R01UH0010EJ0500 Rev.5.00 390
Feb 28, 2012
11.4.4 A/D converter trigger mode selection
Two trigger modes for setting the A/D conversion start timing are available. These trigger modes are set by using the
analog input channel specification register (ADS).
Software trigger mode
Timer trigger mode
(1) Software trigger mode
If a normal start is set by setting the ADTRG0 and ADTRG1 bits, A/D conversion of the analog input channel selected
by ADS will be started by setting ADCS = 1.
After the A/D conversion ends, A/D conversion is successively repeated, unless ADCS = 0 is set.
(2) Timer trigger mode
If TMXn synchronization is set by setting the ADTRG0 and ADTRG1 bits, A/D conversion of the analog input channel
selected by the analog input channel specification register (ADS) will be started when the A/D trigger signal of TMXn
is detected after ADCS = 1 is set.
After the A/D conversion ends, A/D conversion is successively repeated after the A/D trigger signal of TMXn is
detected, unless ADCS = 0 is set.
Cautions 1. Switching the trigger mode should be done after stopping the A/D conversion operation (clearing
(0) ADCS).
2. To select the internal voltage (1.2 V) as an analog input, set the ADCS bit to 1 when at least 10
s
have elapsed after having set the V12SEL bit to 1 while the A/D conversion operation was
stopped (ADCS = 0).
Remark n = 0, 1
11.4.5 A/D converter operation mode
One chann
el of analog input is selected by the analog input channel specification register (ADS) and A/D conversion is
executed.
(1) A/D conversion operation
The A/D conversion operation of the voltage, which is applied to the analog input pin specified by the analog input
channel specification register (ADS), is executed.
When A/D conversion has been completed, the result of the A/D conversion is stored in the A/D conversion result
register, and an interrupt request signal (INTAD) is generated. When one A/D conversion has been completed, the
next A/D conversion operation is immediately started.
If ADS is rewritten during A/D conversion, the A/D conversion operation under execution is stopped and restarted
from the beginning.
If 0 is written to ADCS during A/D conversion, A/D conversion is immediately stopped. At this time, the conversion
result immediately before is retained.
Remark A/D converter analog input pins differ depending on products.
78K0/IY2: ANI0, ANI1, ANI3 to ANI5
78K0/IA2: ANI0 to ANI5
78K0/IB2: ANI0 to ANI8