ATmega64A datasheet(242/392 Pages) ATMEL

Part #	ATmega64A

Description	8-bit Microcontroller with 64K Bytes In-System Programmable Flash

PDF	392 Pages

Scroll/Zoom	100%

Manufacturer	ATMEL [ATMEL Corporation]

Direct Link	http://www.atmel.com

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242 / 392 page

242

8160C–AVR–07/09

ATmega64A

to remove high frequency components with a low-pass filter before applying the signals as

inputs to the ADC.

Figure 23-8. Analog Input Circuitry

23.7.2

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

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

The AVCC pin on the device should be connected to the digital V

CC 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 port pins are used as digital outputs, it is essential that these do not

switch while a conversion is in progress.

ADCn

IIH

1..100 k

CS/H= 14 pF

VCC/2

IIL

ATmega64A Datasheet(PDF) 242 Page - ATMEL Corporation