[avr-chat] Strange programming error

[Ing. Daniel Rozsnyó]

Hi,
  does anybody know what is going on with my setup?

  I am using FT2232H module and an ATmega2560 device. When I try to 
program my firmware, it stops on a verify error, I thought that it is a 
bad flash in the mcu, so I did a full erase, full 0x00 write - all ok. 
Then I tried to add some more strings just to have data over the bad 
location and not code - the result was shocking - the unprogrammed part 
moved!!

  Is the following combination forbidden by the AVR chip, or the FTDI 
uses escaping of data?

  It does not matter how many times I program with erase - the error is 
still on the same position - or more precisely - with the same sequence 
of bytes.

  Please advice me how to solve this issue.. many thanks,

Daniel


$ diff a.hex b.hex
273c273
< 00001100  fc cf 80 91 b9 00 88 7f  80 34 11 f4 81 e0 08 95  
|.........4......|
---
> 00001100  87 ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  
|................|

$ diff c.hex d.hex
369,370c369,370
< 00001700  fc cf 80 91 b9 00 88 7f  80 34 11 f4 81 e0 08 95  
|.........4......|
< 00001710  84 e9 80 93 bc 00 80 e0  08 95 94 ea 90 93 bc 00  
|................|
---
> 00001700  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  
|................|
> 00001710  87 e9 80 93 bc 00 80 e0  08 95 94 ea 90 93 bc 00  
|................|