One-Shot Mode, External Trigger Selected - Renesas M16C Series User Manual

M30240 Group

2.6.2.2 One-shot mode, external trigger selected

In one-shot mode, select functions from those listed in Table 2.28 . An example using the indicated
options is described below. Figure 2.81 shows the timing chart, and Figure 2.82 shows the set-up
procedure.
Table 2.28: A-D converter in one-shot mode (with an external trigger selected) functions
Item
Operation clock ΦAD
O
Resolution O
Analog input pin O
Operation
(1) If the level of the AD
A-D converter begins operating.
(2) After A-D conversion is completed, the content of the successive comparison register (conversion
result) is transmitted to A-D register i. At this time, the A-D conversion interrupt request bit goes to "1".
Also the A-D converter stops operating.
(3) If the level of the AD
step (1) again. If the level of the AD
the A-D converter stops the A-D conversion in process, and carries out the conversion from step (1)
again.
φAD
A-D
"1"
conversion
start flag
"0"
"H"
AD
TRG
"L"
A-D register i
"1"
A-D conversion
interrupt request
"0"
Figure 2.81: Operation timing of one-shot mode with an external trigger selected
Rev.1.00 Sep 24, 2003 Page 235 of 360
Set-up
Divided-by-4 fAD/ divided-by-2
fAD/fAD
8-bit / 10-bit
One of AN pin to AN pin
0 7
changes from "H" to "L" with the A-D conversion start flag set to "1", the
TRG
pin changes from "H" to "L", the A-D converter carries out conversion from
TRG
pin changes from "H" to "L" while conversion is in progress,
TRG
(1) Start A-D conversion
φ
8-bit resolution : 28
AD
10-bit resolution : 33 φ
AD
Set to "1" by software
Cleared to "0" when interrupt request is accepted, or cleared by software
Item
Trigger for starting A-D
conversion
Sample & Hold
(2) A-D conversion is
complete
cycles
cycles
Result
A-D Converter
Set-up
Software trigger
O Trigger by AD
TRG
Not activated
O Activated
(3) Start A-D
conversion