Re: [avrdude-dev] Reset function for arduino

[David A. Mellis]

The schematics may have a resistor, but the boards shipped with a
capacitor or nothing at all.  We've never used a resistor to connect
RTS/DTR and RESET.

The problems that people have been having are because the Arduino IDE
currently uses the "stk500v1" protocol in avrdude, which doesn't
handle reset of RTS and DTR, not the "arduino" protocol that does.
These problems should go away in Arduino 0019, in which the IDE will
toggle both lines before doing uploading.  This is the same problem,
I'm guessing, that Axel is having, which should go away with recent
versions of avrdude that assert the lines on opening the port and
deassert them on closing.

All of which is to say that this patch might not hurt, but I don't
think it's necessary for any of the situations I've encountered.

David

On Tue, Aug 24, 2010 at 9:07 PM, Josef Wolf <address@hidden> wrote:
> On Tue, Aug 24, 2010 at 08:38:13PM +0200, David A. Mellis wrote:
>
>> All of the Arduino boards we've shipped with auto-reset have used a
>> capacitor, not a resistor, to connect RTS/DTR to the microcontroller's reset
>> pin, so I'm not sure this is necessary.
>
> Well, I see lots of schematics (e.g. the NG, the Diecimila) with a resistor
> instead of a capacitor. And people keep having problems. One of the recent
> examples is http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1280814595
> I have purchased such a cable, and indeed, I had similar problems.
>
>> Also, which operating systems have you tested this on?
>
> I tested on opensuse and ubuntu. Same results.
>
>> Do they all allow
>> raising and lowering of the line once the serial device is open?
>
> If an OS does not allow this, current code will not work anyway on that OS.
>
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