Operation Of A/D Converter (One-Shot Mode) - Renesas M30245 Series User Manual

M30245 Group

2.9.2 Operation of A/D converter (one-shot mode)

In one-shot mode, choose functions from those listed in Table 2.9.2. Operations of the circled items are
described below. Figure 2.9.4 shows the operation timing, and Figure 2.9.5 shows the set-up procedure.
Table 2.9.2. Choosed functions
Item
Operation clock
φ
AD
Resolution
Analog input pin
Trigger for starting
A/D conversion
Sample & Hold
Operation
(1) Setting the A/D conversion start flag to "1" causes the A/D converter to begin operating.
(2) After A/D conversion is completed, the content of the successive comparison register (con-
version result) is transmitted to AD register i. At this time, the A/D conversion interrupt re-
quest bit goes to "1". Also, the A/D conversion start flag goes to "0", and the A/D converter
stops operating.
φ
A D
"1"
A / D c o n v e r s i o n
s t a r t f l a g
"0"
A D r e g i s t e r i
"1"
A/D conversion
interrupt request
"0"
N o t e : W h e n φ
A D
C o n v e r s i o n r a t e p e r a n a l o g i n p u t p i n i s 4 9 φ
Figure 2.9.4. Operation timing of one-shot mode
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
Set-up
Divided-by-4 f
O
by-3 f / divided-by-2 f
AD
O 8-bit / 10-bit
O One of AN
0
O Software trigger
Trigger by AD
Not activated
O Activated
(1) Start A/D conversion
8-bit resolution : 28 φ
10-bit resolution : 33 φ
Set to "1" by software
C l e a r e d t o " 0 " w h e n i n t e r r u p t r e q u e s t i s a c c e p t e d , o r c l e a r e d b y s o f t w a r e
f r e q u e n c y i s l e s s t h a n 1 M H , s a m p l e a n d h o l d f u n c t i o n c a n n o t b e s e l e c t e d .
Z
page 218 of 354
/ divided-
AD
/ f
AD AD
pin to AN pin
7
TRG
cycles
AD
cycles
AD
c y c l e s f o r 8 - b i t r e s o l u t i o n a n d 5 9 φ
A D
2. A/D Converter
( 2 ) A / D c o n v e r s i o n i s c o m p l e t e
R e s u l t
c y c l e s f o r 1 0 - b i t r e s o l u t i o n .
A D