AVR-Chat

Dave (and Mike), I tried all sorts of delays but none worked.  In the process of doing this I discovered that my tests to determine if the board was still powered by the RX/TX lines were faulty, and as it turns out that *is* the source of the problem.  The board is not actually turning off.  

 

Ideas on how to fix this?   Series resistors in the RX/TX lines?

 

Thanks, Steve

 

From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf Of Dave McLaughlin
Sent: Friday, December 13, 2013 6:31 PM
To: AVR-Chat@yahoogroups.com
Subject: RE: [AVR-Chat] RE: initial flash programming run versus subsequent runs

 

  

Hi Steve,

 

What happens if you put in a delay at the start before you send the byte?

 

What fuse settings do you have for startup? I've never used the fast options, always slow start and this has proven reliable.

 

On a system I did years ago, I had a similar issue with the serial port. I had to put in a 1 second delay before I started to send any data. This I think was way back with an AT90S8515

 

The other issue could be with your RS232 drivers. What are you using here? I've seen an issue in the past where the startup power timing for the POS and NEG supplies was slow although modern devices should be fast these days. This was with the older IC's using 1uF caps. Worth checking here though.

 

Dave…

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Very funny Scotty, now beam down my clothes…

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From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf Of Steven Hodge
Sent: 14 December 2013 08:34
To: AVR-Chat@yahoogroups.com
Subject: RE: [AVR-Chat] RE: initial flash programming run versus subsequent runs

 

  

Thanks for reminding me of that.  I once had that happen to me too.  However, I just ran some tests and it’s not the case here.  I disconnected the programmer and turned off the board power.  I  then removed the serial lines (leaving the GND connected to the adapter) and re-connected them.  No bytes came out and it did not respond to switch changes, so I assume the processor was (correctly) not powered on.   Turn on the board power and it does respond to switch changes but, as before, no wake-up byte.

 

Steve

 





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