[avrdude-dev] [bug #39690] Erase-rewrite cycle counter non-functional for ATxmega parts

[David Glaze]

URL:
  <http://savannah.nongnu.org/bugs/?39690>

                 Summary: Erase-rewrite cycle counter non-functional for
ATxmega parts
                 Project: AVR Downloader/UploaDEr
            Submitted by: djglaze
            Submitted on: Sun 04 Aug 2013 04:33:21 PM GMT
                Category: None
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
                 Privacy: Public
             Assigned to: None
         Originator Name: David Glaze
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any

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Details:

There are several issues I have found with using avrdude's erase-rewrite cycle
counter (-y) functionality with ATxmega parts.  (I have only confirmed this
with an ATxmega128A3U, but I strongly suspect the issue would be the same for
other ATxmega models.)

The ATxmega parts appear to support both an atomic write operation and a
"split" write operation for the EEPROM, where an erase occurs automatically
only for the atomic write.  The EEPROM byte writing operations issued by
Avrdude for the cycle counter appear to trigger a split write operation on the
device, meaning that an explicit byte erase must be performed beforehand. 
This is not done by Avrdude, as it only supports a page erase.

This behavior can be observed by doing a complete erase of the EEPROM, and
then manually writing a value to the cycle counter address (-Y).  Any value
chosen will be written successfully.  Any subsequent values written will only
switch bits from 1 to 0.  Here is an attempt to write 15 (0x0F) and then write
240 (0xF0):


$ avrdude -c dragon_pdi -P usb -p x128a3 -v -Y 15

avrdude: Version 6.0rc1, compiled on Aug  4 2013 at 09:53:33
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2009 Joerg Wunsch

         System wide configuration file is
"/home/avarice/dave/local/etc/avrdude.conf"
         User configuration file is "/home/avarice/dave/.avrduderc"
         User configuration file does not exist or is not a regular file,
skipping

         Using Port                    : usb
         Using Programmer              : dragon_pdi
avrdude: usbdev_open(): Found AVRDRAGON, serno: 00A200034199
JTAG ICE mkII sign-on message:
Communications protocol version: 1
M_MCU:
  boot-loader FW version:        255
  firmware version:              7.34
  hardware version:              1
S_MCU:
  boot-loader FW version:        255
  firmware version:              7.34
  hardware version:              7
Serial number:                   00:a2:00:03:41:99
Device ID:                       AVRDRAGON
         AVR Part                      : ATxmega128A3
         Chip Erase delay              : 0 us
         PAGEL                         : P00
         BS2                           : P00
         RESET disposition             : dedicated
         RETRY pulse                   : SCK
         serial program mode           : yes
         parallel program mode         : yes
         Timeout                       : 0
         StabDelay                     : 0
         CmdexeDelay                   : 0
         SyncLoops                     : 0
         ByteDelay                     : 0
         PollIndex                     : 0
         PollValue                     : 0x00
         Memory Detail                 :

                                  Block Poll               Page               
       Polled
           Memory Type Mode Delay Size  Indx Paged  Size   Size #Pages MinW 
MaxW   ReadBack
           ----------- ---- ----- ----- ---- ------ ------ ---- ------ -----
----- ---------
           prodsig        0     0     0    0 no        512  512      0     0  
  0 0x00 0x00
           usersig        0     0     0    0 no        512  512      0     0  
  0 0x00 0x00
           signature      0     0     0    0 no          3    0      0     0  
  0 0x00 0x00
           fuse1          0     0     0    0 no          1    0      0     0  
  0 0x00 0x00
           fuse2          0     0     0    0 no          1    0      0     0  
  0 0x00 0x00
           fuse4          0     0     0    0 no          1    0      0     0  
  0 0x00 0x00
           fuse5          0     0     0    0 no          1    0      0     0  
  0 0x00 0x00
           lock           0     0     0    0 no          1    0      0     0  
  0 0x00 0x00
           data           0     0     0    0 no          0    0      0     0  
  0 0x00 0x00
           eeprom         0     0     0    0 no       2048   32      0     0  
  0 0x00 0x00
           application    0     0     0    0 no     131072  512      0     0  
  0 0x00 0x00
           apptable       0     0     0    0 no       8192  512      0     0  
  0 0x00 0x00
           boot           0     0     0    0 no       8192  512      0     0  
  0 0x00 0x00
           flash          0     0     0    0 no     139264  512      0     0  
  0 0x00 0x00
           fuse0          0     0     0    0 no          1    0      0     0  
  0 0x00 0x00

         Programmer Type : DRAGON_PDI
         Description     : Atmel AVR Dragon in PDI mode
         M_MCU hardware version: 1
         M_MCU firmware version: 7.34
         S_MCU hardware version: 7
         S_MCU firmware version: 7.34
         Serial number:          00:a2:00:03:41:99
         Vtarget         : 3.3 V

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.04s

avrdude: Device signature = 0x1e9742
avrdude: setting erase-rewrite cycle count to 15

avrdude done.  Thank you.



$ ~/code/avrdude-svn/trunk/avrdude/avrdude -c dragon_pdi -P usb -p x128a3 -Y
240

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.15s

avrdude: Device signature = 0x1e9742
avrdude: current erase-rewrite cycle count is 15
avrdude: setting erase-rewrite cycle count to 240

avrdude done.  Thank you.


The last row of data from a hex dump of the EEPROM after the first and second
operations above is:


:2007E000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF0000000F06



:2007E000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF0000000015


Note that the last 4 bytes should be 0x000000F0 after the second operation,
and not 0x00000000.

In my local copy of avrdude, I have crudely hacked in a byte erase prior to a
byte write for the EEPROM as a proof of concept, and confirmed that it works
as expected for the AVR Dragon programmer.

The JTAGICE3 programmer has other issues on top of this.  There is a buffer
overrun (that I will submit in a separate ticket), and an attempt to hack in
similar support yields bizarre behavior where after issuing a MTYPE_EEPROM
(0x22) write command, an error comes back saying that the MTYPE_SPM (0xA0)
write command failed.  It's probably best if I don't submit my attempted
fixes, to let the experts craft the correct solution for this
reverse-engineered communication protocol.





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