bugAVR Downloader/UploaDEr - Bugs: bug #21079, slow EEPROM write: unchanged bytes...

 
 

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bug #21079: slow EEPROM write: unchanged bytes should be skipped

Submitter:  Tamas Fenyvesi <fenyvesi>
Submitted:  Fri 14 Sep 2007 03:16:30 PM UTC
   
 
Category:  None Severity:  3 - Normal
Priority:  5 - Normal Item Group:  None
Status:  Fixed Privacy:  Public
Assigned to:  joerg_wunsch Originator Name:  Tamas Fenyvesi
Open/Closed:  Closed Release:  None
Programmer hardware:  Device type: 

Wed 11 Sep 2013 04:30:12 PM UTC, comment #1: 

As AVRDUDE now (SVN version, to be released as 6.0 soon) only
programs those locations that are present in the input file
(rounded to full pages for flash), I consider this being fixed.

Joerg Wunsch <joerg_wunsch>
Group administrator
Fri 14 Sep 2007 03:16:30 PM UTC, original submission:  

Hello,
I've just tried out avrdude5.4 with USBisp (a fast programming tool) and I found (e.g. on ATmega128) it is some three times slower to write the 4k EEPROM than the 128k flash.

This is a bad combination of
a.) being EEPROM write not paged in serial prg mode and
b.) that AVRdude doesn't skip the positions that not exists in .eep file.
It sweeps all the area byte by byte even for burning one 0xff (i.e. nothing).

However, Datasheet writes 0xff bytes can be skipped at erased device.
On the other hand, EEPROM content can be preserved from erasing so it's not sure that all given byte position has been empty.

1. One possibile speed enhancement is to write only the bytes that are described in .eep file.

2. Even better to read all the EEPROM (at least the bytes that exist in .eep file), and to compare each byte with the new values. Only changing bytepositions shall be written.

3. Similarly, empty (all 0xff) FLASH pages should be skipped.

4. All FLASH areas that are not mentioned in .hex can be skipped. User program won't intentionally jump over there. OK, this might be optional by a command line switch (e.g. "fillout").

Best regards,
Tamas

Tamas Fenyvesi <fenyvesi>

 

(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

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    Follow 3 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2013-09-11 joerg_wunsch StatusNone Fixed
        Assigned toNone joerg_wunsch
        Open/ClosedOpen Closed

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