Renesas M32R/ECU Series User Manual page 490

11
Table 11.5.1 Sampling Time (in Which C2 Needs to Be Charged)
Conversion start method Conversion speed
Single mode Slow mode
(when sample-and
-hold disabled) Fast mode
Single mode Slow mode
(when sample-and
-hold enabled) Fast mode
Comparator mode Slow mode
Fast mode
Therefore, the time in which C2 needs to be charged is found from Eq. B-1, as follows:
Sampling time (in which C2 needs to be charged) > Cin × R1 + C2(R1 + R2) --- Eq. B2
Thus, the maximum value of R1 can be obtained as a criterion from the equation below. Note, however, that
for single mode (when sample-and-hold is disabled), the sampling time for the second and subsequent bits
(C2 charging time) must be applied.
C2 charging time - C2 × R2
R1 <
Sampling time for the first bit
Normal speed
Double speed
Normal speed
Double speed
Normal speed
Double speed
Normal speed
Double speed
Normal speed
Double speed
Normal speed
Double speed
Cin + C2
11.5 Precautions on Using A-D Converters
Sampling time for the second and subsequent bits
27.5BCLK
15.5BCLK
11.5BCLK
7.5BCLK
27.5BCLK
15.5BCLK
11.5BCLK
7.5BCLK
27.5BCLK
15.5BCLK
11.5BCLK
7.5BCLK
11-45
A-D Converters
13.5BCLK
7.5BCLK
5.5BCLK
3.5BCLK
–
–
–
–
–
–
–
–
32180 Group User's Manual (Rev.1.0)