AVR-Chat

Hi Matt,

 

My first thought looking at your image is that you have no capacitors fitted
to the crystal circuit so you may have an unstable internal reference which
may affect the baud rate. 

 

With the 16Mhz crystal I would suggest you put in a 22pF cap between each
crystal pin and GND. This is shown in the datasheet for the device on page
30.

 

I would also fit a reservoir capacitor on the output of the voltage
regulator. Even though your load is very small, it is good practice to do
this as those linear regulators are known to be noisy if not bypassed. Fit a
4.7uF Electrolytic (and a 0.1uF ceramic in parallel) between ground and the
5V output.

 

You would be amazed at how often a microcontroller fails due to poor power
supply decoupling. When I was first learning to do electronics and
programming I used to just build without and wonder why it would crash every
so often. After learning about good decoupling, my designs since then have
been rock solid. :o)

 

Hope you get it working.

 

Dave.

 

From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of Matthew Metzger
Sent: 24 October 2011 01:08
To: AVR-Chat@yahoogroups.com
Subject: [AVR-Chat] Hello and Question

 

  

Hello. I am new to the group and an am an amateur in the electronics field.
I am looking forward to learning and participating.

That having been said, I am trying to write code to an Atmega chip with the
Arduino bootloader I've done this before with similar chips with different
bootloaders without problem but I cannot seem to get it going on the arduino
chip. Anyway, long story short, I used this video (
http://www.youtube.com/user/Halo2maniaccc#p/u/9/VY0kiJNI5oE ) for direction.
Here is my board ( http://centrasupport.com/electronics/Arduino.png ) I am
using a different 16mhz crystal oscillator and, when I took this photo, was
using a switch instead of a button for reset. I am now using a button. I get
a blip in the blink pattern when I try to upload new code. But, at the end
of all I always end up with the following:

Binary sketch size: 1018 bytes (of a 32256 byte maximum)
avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

Any ideas on what I am doing wrong? I am also not opposed to building
another board if someone has a better setup. The main requirement is that
it's for the arduino bootloader.

Thanks in advance for any advice you can give.

- Matt





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