ATmega32A datasheet(217/352 Pages) ATMEL

Part #	ATmega32A

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

PDF	352 Pages

Scroll/Zoom	100%

Manufacturer	ATMEL [ATMEL Corporation]

Direct Link	http://www.atmel.com

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217 / 352 page

217

8155B–AVR–07/09

ATmega32A

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

inputs to the ADC.

Figure 22-8. Analog Input Circuitry

22.7.2

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

analog 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 22-9.

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

ATmega32A Datasheet(PDF) 217 Page - ATMEL Corporation