bugAVR Downloader/UploaDEr - Bugs: bug #26910, Terminal mode over USB/Dragon:...


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bug #26910: Terminal mode over USB/Dragon: dumping Flash is extremely slow

Submitted by:  Vincent Trouilliez <troutrou>
Submitted on:  Mon 29 Jun 2009 03:11:42 PM UTC  
Category: NoneSeverity: 1 - Wish
Priority: 1 - LaterItem Group: None
Status: FixedPrivacy: Public
Assigned to: Joerg Wunsch <joerg_wunsch>Originator Name: Vincent Trouilliez
Open/Closed: ClosedRelease: None
Programmer hardware: Device type: 

Wed 11 Sep 2013 04:06:58 PM UTC, comment #2:

Since the byte read functions of the more sophisticated
programmer types (JTAGICEmkII, STK500v2, JTAGICE3) use a
page cache, this should be no longer an issue.

Dumping 1 KiB of flash contents of an ATmega128RFA1 in
terminal mode is now seemingly instantaneous (no noticable
response time at all).

Joerg Wunsch <joerg_wunsch>
Project AdministratorIn charge of this item.
Wed 01 Jul 2009 03:57:08 PM UTC, comment #1:

Sorry, no resources available to implement it.
If you care implementing it, please file a patch as an

Joerg Wunsch <joerg_wunsch>
Project AdministratorIn charge of this item.
Mon 29 Jun 2009 03:11:42 PM UTC, original submission:

I really love the terminal mode. I used to have a DIY parport cable, and dumping Flash content was blazingly fast, I used it often. However I have now purchased a Dragon to replace my DIY cable, and it appears that dumping a single tiny litle KB of data takes... 60 seconds ! IOW, this feature has become useless :-(

I enquired a lot on avr-chat, and it would seem that the problem is due to avrdude reading Flash bytes one at a time, and that although this is fast over parport, it's is extremely inefficient over USB, because of the very nature of USB.

So I think this could be fixed simply by NOT reading bytes one by one, but instead read a block of for example 2KB (which takes about one second, this is fast enough), regardless of how many bytes the user asked for. So if, say, I ask for 128 bytes, avrdude reads 2KB in one go, in order to retrieve data quickly, then displays only the first 128 bytes (or whatever the user asked for) on the screen.
This way the user gets to see the data very fast, no matter if he asked for just a few bytes, or a few KB's.

Vincent Trouilliez <troutrou>


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    Follow 5 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Wed 11 Sep 2013 04:06:58 PM UTCjoerg_wunschStatusNone=>Fixed
      Assigned toNone=>joerg_wunsch
    Wed 01 Jul 2009 03:57:08 PM UTCjoerg_wunschSeverity3 - Normal=>1 - Wish
      Priority5 - Normal=>1 - Later

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