ATmega328P datasheet(250/345 Pages) ATMEL

Part #	ATmega328P

Description	8-bit Microcontroller with 32K Bytes In-System Programmable Flash

PDF	345 Pages

Scroll/Zoom	100%

Manufacturer	ATMEL [ATMEL Corporation]

Direct Link	http://www.atmel.com

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250 / 345 page

250

7810A–AVR–11/09

ATmega328P [Preliminary]

Figure 23-8. Analog Input Circuitry

23.6.2

Analog Noise Canceling Techniques

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:

Keep analog signal paths as short as possible. Make sure analog tracks run over the

analog ground plane, and keep them well away from high-speed switching digital

tracks.

The AV

CC pin on the device should be connected to the digital VCC supply voltage via

an LC network as shown in Figure 23-9.

Use the ADC noise canceler function to reduce induced noise from the CPU.

If any ADC [3..0] port pins are used as digital outputs, it is essential that these do not

switch while a conversion is in progress. However, using the 2-wire Interface (ADC4

ADCn

IIH

1..100 k

CS/H= 14 pF

VCC/2

IIL

ATmega328P Datasheet(PDF) 250 Page - ATMEL Corporation