m5m51016btp Renesas Electronics Corporation., m5m51016btp Datasheet - Page 239

• Manufacturer Part Number: m5m51016btp
• Description: Renesas 16-bit Single-chip Microcomputer M16c Family / M16c/20 Series
• Manufacturer: Renesas Electronics Corporation.

M30245 Group
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
Figure 2.9.17. Use of capacitors to reduce noice
2.9.8 Precautions for A/D Converter
(1) Write to each bit (except bit 6) of AD control register 0, to each bit of AD control register 1, and
(2) To reduce conversion error due to noise, connect a voltage to the AVcc pin and to the Vref pin from
(3) Set the direction register of the following ports to input: the port corresponding to a pin to be
(4) Rewrite to analog input pin after changing A/D operation mode.
(5) When using the one-shot or single sweep mode
(6) When using the repeat mode or repeat sweep mode 0 or 1
(7) In using a key-input interrupt, none of the 8 pins (AN
(8) Use AD under 10 MHz. When X
to bit 0 of AD control register 2 when A/D conversion is stopped (before a trigger occurs).
In particular, when the Vref connection bit is changed from 0 to 1, start A/D conversion after
an elapse of 1 µs or longer.
an independent source. It is recommended to connect a capacitor between the AVss pin and the
AVcc pin, between the AVss pin and the Vref pin, and between the AVss pin and the analog input
pin (ANi). Figure 2.9.17 shows the an example of connecting the capacitors to these pins.
used as an analog input pin and external trigger input pin (P9
conversion port (if the A/D input voltage goes to “L” level, a key-input interrupt occurs).
Microcomputer
Confirm that A/D conversion is complete before reading the AD register.
(Note: When A/D conversion interrupt request bit is set, it shows that A/D conversion is completed.)
Use the undivided main clock as the internal CPU clock.
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AV
AV
V
V
AN
REF
CC
CC
SS
i
C1
C3
C2
Note
Note
IN
is over 10 MHz, divide it.
1:
2:
C1 0.47 µF, C2 0.47 µF, C3 100 pF
(for reference)
Use thick and shortest possible wiring
to connect capacitors.
0
through AN
3
).
7
) can be used as an A/D
2. A/D Converter