CHAPTER 13 A/D CONVERTER
Page 306 of 920
13.6
A/D Converter Operation Modes
The operation of each A/D converter mode is described below. In addition, the procedure for specifying each mode
is described in
13.7 A/D Converter Setup Flowchart
13.6.1
Software trigger mode (select mode, sequential conversion mode)
<1> In the stop status, the ADCE bit of A/D converter mode register 0 (ADM0) is set to 1, and the system
enters the A/D conversion standby status.
<2> After the software counts up to the stabilization wait time (1
μ
s), the ADCS bit of the ADM0 register is
set to 1 to perform the A/D conversion of the analog input specified by the analog input channel
specification register (ADS).
<3> When A/D conversion ends, the conversion result is stored in the A/D conversion result register
(ADCR, ADCRH), and the A/D conversion end interrupt request signal (INTAD) is generated. After
A/D conversion ends, the next A/D conversion immediately starts.
<4> When ADCS is overwritten with 1 during conversion operation, the current A/D conversion is
interrupted, and conversion restarts. The partially converted data is discarded.
<5> When the value of the ADS register is rewritten or overwritten during conversion operation, the
current A/D conversion is interrupted, and A/D conversion is performed on the analog input
respecified by the ADS register. The partially converted data is discarded.
<6> Even if a hardware trigger is input during conversion operation, A/D conversion does not start.
<7> When ADCS is cleared to 0 during conversion operation, the current A/D conversion is interrupted,
and the system enters the A/D conversion standby status.
<8> When ADCE is cleared to 0 while in the A/D conversion standby status, the A/D converter enters the
stop status. When ADCE = 0, specifying 1 for ADCS is ignored and A/D conversion does not start.
Figure 13 - 18 Example of Software Trigger Mode (Select Mode, Sequential Conversion Mode) Operation Timing
ADCE
ADCS
ADS
INTAD
A/D conversion
status
Conversion
stops
ADCR,
ADCRH
<1> ADCE is set to 1.
ADCS is set to 1 while in the
conversion standby status.
ADCE is cleared to 0. <8>
ANI0
ANI1
<3>
Conversion
standby
Data 1
(ANI0)
Data 2
(ANI0)
Data 1
(ANI0)
Data 3
(ANI0)
Data 4
(ANI0)
Data 2
(ANI0)
Data 5
(ANI0)
Data 4
(ANI0)
Data 6
(ANI1)
Data 7
(ANI1)
Data 6
(ANI1)
Data 8
(ANI1)
Data 7
(ANI1)
Conversion
standby
Conversion
stops
Conversion is activated
<3>
<2>
ADCS is overwritten
with 1 during A/D
conversion operation.
<4>
A hardware trigger is
generated
(and ignored).
<6>
<7>
ADCS is cleared
to 0 during A/D
conversion operation.
<5>
ADS is rewritten during
A/D conversion operation
(from ANI0 to ANI1).
Conversion is
interrupted.
Conversion is
Interrupted and
restarts after the
conversion start
time has elapsed.
<3>
A/D conversion
ends and the next
conversion starts.
<3>
<3>
Summary of Contents for RL78/G1H
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