atmega32c1 ATMEL Corporation, atmega32c1 Datasheet - Page 235

• Manufacturer Part Number: atmega32c1
• Description: Atmega32m1 Automotive 8-bit Avr Microcontroller With 32k/64k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

18.6.2
7647A–AVR–02/08
Analog Noise Canceling Techniques
Figure 18-8. Analog Input Circuitry
Digital circuitry inside and outside the device generates EMI which might affect the accuracy of
analog measurements. If conversion accuracy is critical, the noise level can be reduced by
applying the following techniques:
Figure 18-9. ADC Power Connections
(ACMPN3/ADC0) PE2
1. Keep analog signal paths as short as possible. Make sure analog tracks run over the
2. The AV
3. Use the ADC noise canceler function to reduce induced noise from the CPU.
4. If any ADC port pins are used as digital outputs, it is essential that these do not
analog ground plane, and keep them well away from high-speed switching digital
tracks.
an LC network as shown in
switch while a conversion is in progress.
(ADC1) PD4
CC
pin on the device should be connected to the digital V
GND
VCC
ADCn
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Figure
I
IH
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
18-9.
I
IL
PB7(ADC4)
PB6 (ADC7)
PB5 (ADC6/ACMPN1/AMP2-)
PC7 (D2A/AMP2+)
PB4 (AMP0+)
PB3 (AMP0-)
PC6 (ADC10/ACMP1)
AREF (ISRC)
AGND
AVCC
PC5 (ADC9/ACMP3/AMP1+)
PC4 (ADC8/AMP1-)
PB2 (ADC5/ACMPN0)
PD7 (ACMP0)
PD6 (ADC3/ACMPN2)
PD5 (ADC2/ACMP2)
Analog Ground Plane
1..100 kΩ
ATmega32/64/M1/C1
C
S/H
= 14 pF
CC
V
CC
supply voltage via
/2
100nF
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