AVR-Chat

Generally speaking you ALWAYS need bypass capacitors.  The AVR chips
generate a lot of power supply spikes which the bypass capacitors
"bypass" to ground.

Bypass capacitors should be placed as close as possible to the power
supply pins of your chip.

In fact, it's best if you can run your supply lines directly to the
bypass capacitors rather than run them directly to the pins of your
chip.  This helps keep the impedance of your noise bypass system as low
as possible.

Also, it's best to run all of your grounds and V+ supply lines to a
"single point" on each side, but usually this is not necessary.

If your power supply is off-board, you should put a capacitor where the
power comes in.  A low ESR capacitor is best but not usually necessary.

Clean supply lines are critical in microprocessor applications.  Just
put a scope on your supply lines someday and take a look at all the
noise which is generated by your CPU.

Barry

-----Original Message-----
From: JChavez@soboce.com [mailto:JChavez@soboce.com] 
Sent: Friday, March 12, 2004 5:38 AM
Subject: Re: [AVR-Chat] It just rests

I forgot to mention a normal computer power supply feeds my board. Do
you
think I still need the bypass caps?

JAvier

VA3TO <hduff@cogeco.ca> con fecha 11/03/2004 02:03:14 p.m.

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CC:
Asunto: Re: [AVR-Chat] It just rests

Oops...that's bypass, not baypass :)

VA3TO wrote:

>How about baypass caps on the uC power supply pin(s) ?
>And what are you using for a reset circuit ?
>Hugh
>
>
>JChavez@soboce.com wrote:
>
>
>
>>I made a little project using the atmega8515, it runs nicely however
when
>>someone turns on a drill that's one meter far away the uc resets. Then
I
>>realize that the mc resets all the time a big motor starts. Is there
>>something I should consider?
>>
>>Javier Chavez
>>
>>


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