[avrdude-dev] [bug #41631] TPI bitbang for preprogrammed ATtinys can fail (Patch attached)

[Matthias Neeracher]

URL:
  <http://savannah.nongnu.org/bugs/?41631>

                 Summary: TPI bitbang for preprogrammed ATtinys can fail
(Patch attached)
                 Project: AVR Downloader/UploaDEr
            Submitted by: microtherion
            Submitted on: Tue 18 Feb 2014 01:13:56 PM GMT
                Category: None
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
                 Privacy: Public
             Assigned to: None
         Originator Name: Matthias Neeracher
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any

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Details:

If an ATtiny4/5/9/10 has been programmed with software that sets PB0 (a.k.a
TPIDATA) as an output, this will interfere with the MOSI -> MISO connectivity
test when avrdude tries to reprogram the MCU. 

The simplest solution, it seems to me, is to hold RESET low during the
MOSI->MISO test. I’ve attached a patch implementing this, which works for me
(Using a Buspirate as the programmer).





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File Attachments:


-------------------------------------------------------
Date: Tue 18 Feb 2014 01:13:56 PM GMT  Name: bitbang,patch  Size: 554B   By:
microtherion

<http://savannah.nongnu.org/bugs/download.php?file_id=30594>

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