[avrdude-dev] Why is eeprom file overwritten?

[Bob Paddock]

Today is my first adventure at using AVRDUDE to program
EEPROM while programming the flash, using AVRDUDE 4.4.0.

I start out with two files irmem.hex for flash, and irmem.eep
both in Intel hex format.

After using this command line:

avrdude -p atmega162 -P com1 -c stk500 -v -v \
 -U flash:w:irmem.hex -U eeprom:w:irmem.eep

My irmem.eep file now looks like this, and my eeprom is still
blank when I read it:

:00000001FF

If I leave off either -U eeprom... or both -U eeprom and -U flash,
irmem.eep is created with the above contents, which I don't understand.

It seems to be the signature read that is overwriting the eeprom file.

My work-around is to call the eeprom file eeprom.eep rather than  
$(TARGET).eep.

Here is full output:

avrdude: Version 4.4.0
         Copyright (c) 2000-2004 Brian Dean, address@hidden

         System wide configuration file is "C:\WINAVR\BIN\avrdude.conf"

         Using Port            : com1
         Using Programmer      : stk500
         AVR Part              : ATMEGA162
         Chip Erase delay      : 9000 us
         PAGEL                 : PD7 [I added PAGEL and BS2 to config  
file.]
         BS2                   : PA0
         RESET disposition     : dedicated
         RETRY pulse           : SCK
         serial program mode   : yes
         parallel program mode : yes
         Memory Detail         :

                                     Page                       Polled
           Memory Type Paged  Size   Size #Pages MinW  MaxW   ReadBack
           ----------- ------ ------ ---- ------ ----- ----- ---------
           flash       yes     16384  128   128  4500  4500 0xff 0xff
           eeprom      no        512    0     0  9000  9000 0xff 0xff
           lfuse       no          1    0     0 16000 16000 0x00 0x00
           hfuse       no          1    0     0 16000 16000 0x00 0x00
           efuse       no          1    0     0 16000 16000 0x00 0x00
           lock        no          1    0     0 16000 16000 0x00 0x00
           signature   no          3    0     0     0     0 0x00 0x00
           calibration no          1    0     0     0     0 0x00 0x00

         Programmer Type : STK500
         Description     : Atmel STK500
         Hardware Version: 2
         Firmware Version: 1.18
         Vtarget         : 3.0 V
         Varef           : 3.0 V
         Oscillator      : 3.686 MHz
         SCK period      : 1.1 us

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.00s
[My irmem.eep is now gone.]
avrdude: Device signature = 0x1e9404
avrdude: NOTE: FLASH memory has been specified, an erase cycle will be  
performed
         To disable this feature, specify the -D option.
avrdude: erasing chip
avrdude: reading input file "irmem.hex"
avrdude: input file irmem.hex auto detected as Intel Hex
avrdude: writing flash (10956 bytes):

Writing | ################################################## | 100% 3.49s

avrdude: 10956 bytes of flash written
avrdude: verifying flash memory against irmem.hex:
avrdude: load data flash data from input file irmem.hex:
avrdude: input file irmem.hex auto detected as Intel Hex
avrdude: input file irmem.hex contains 10956 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 2.95s

avrdude: verifying ...
avrdude: 10956 bytes of flash verified
avrdude: reading input file "irmem.eep"
avrdude: input file irmem.eep auto detected as Intel Hex
avrdude: writing eeprom (0 bytes):

Writing | ################################################## | 100% 0.00s

avrdude: 0 bytes of eeprom written
avrdude: verifying eeprom memory against irmem.eep:
avrdude: load data eeprom data from input file irmem.eep:
avrdude: input file irmem.eep auto detected as Intel Hex
avrdude: input file irmem.eep contains 0 bytes
avrdude: reading on-chip eeprom data:

Reading | ################################################## | 100% 0.14s

avrdude: verifying ...
avrdude: 0 bytes of eeprom verified

avrdude done.  Thank you.