[avr-gcc-list] AVR109-GCC bootloader problem on mega8

[Mattew Fornero]

I'm attempting to setup a bootloader for the ATmega8 using the avr109
app note posted here. I'm using the GCC version included in it, along
with the WinAVR toolchain.

Using the preprocessor.xls file, I've setup my bootloader to have
1024 words of memory, starting at address 0xc00. The chip runs off the
interal RC oscillator at 8MHz, with a baud rate of 19200. I've changed
the partcode from 0x77 to 0x76 in order for AVRDUDE to correctly detect
it.

I've also modified the bootloader to write the OSCAL register at
startup to the calibration value found using the stk500 tool in
AVRStudio 4

AVRDUDE is then able to communicate with the bootloader via the UART, correctly reads the fuses, signature bytes, etc.

It appears to erase/write memory correctly, but the process fails when performing verify at the end of a .hex download.

avrdude: verification error, first mismatch at byte 0x0000
         0x12 != 0xff

When I use either the stk500 or the bootloader to read flash memory
out to a file, I see all Fs (unprogrammed) until the bootloader
section, which contains the correct hex data for my code. It seems that
the bootloader is correctly interfacing to AVRDUDE, correctly reading
flash memory, but is not writing it correctly.

I've checked the fuse and lock bit settings-- each appear to be correct:

Fuses: H = 0xD8 (bootsize = 1024, boot reset vector enabled)
           L = 0xE4 (clk = 8mhz interal osc, startup = 6ck + 64ms)
Lock bits = 0xFF (no mem lock, no app section protection, no boot section protection)

I've also tried adding the following command to the main loop of the bootloader:

else if(val =='Z')
         {
            temp_int = 0xabcd;
            address = 0;
            _WAIT_FOR_SPM();
            _PAGE_ERASE( address );
            _WAIT_FOR_SPM();
            _FILL_TEMP_WORD( address, temp_int);
            _WAIT_FOR_SPM();
            _PAGE_WRITE( address << 1 );
            _WAIT_FOR_SPM();
            _ENABLE_RWW_SECTION();
            sendchar('!');
            sendchar('\r');
         }

Using a terminal program, I've sent the "Z" command and gotten the
expected "!" and line feed, but see no change to the contents of memory
when reading it back out.

Anyone know what might be going wrong here?

(AVRDUDE log file):

C:\WinAVR\bin\avrdude -p atmega8 -P com2 -c avr109  -v -v  -U flash:w:main.hex

avrdude: Version 5.0
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/

         System wide configuration file is "C:\WinAVR\bin\avrdude.conf"

         Using Port            : com2
         Using Programmer      : avr109
         AVR Part              : ATMEGA8
         Chip Erase delay      : 10000 us
         PAGEL                 : PD7
         BS2                   : PC2
         RESET disposition     : dedicated
         RETRY pulse           : SCK
         serial program mode   : yes
         parallel program mode : yes
         Timeout               : 200
         StabDelay             : 100
         CmdexeDelay           : 25
         SyncLoops             : 32
         ByteDelay             : 0
         PollIndex             : 3
         PollValue             : 0x53
         Memory Detail         :

                                  Block Poll               Page                       Polled
           Memory Type Mode Delay Size  Indx Paged  Size   Size #Pages MinW  MaxW   ReadBack
           ----------- ---- ----- ----- ---- ------ ------ ---- ------ ----- ----- ---------
           eeprom         4    10   128    0 no        512    0      0  9000  9000 0xff 0xff
           flash         33     6    64    0 yes      8192   64    128  4500  4500 0xff 0x00
           lfuse          0     0     0    0 no          1    0      0  2000  2000 0x00 0x00
           hfuse          0     0     0    0 no          1    0      0  2000  2000 0x00 0x00
           lock           0     0     0    0 no          1    0      0  2000  2000 0x00 0x00
           calibration    0     0     0    0 no          4    0      0     0     0 0x00 0x00
           signature      0     0     0    0 no          3    0      0     0     0 0x00 0x00

         Programmer Type : avr910
         Description     : Atmel AppNote AVR109 Boot Loader

Connecting to programmer: .
Found programmer: Id = "AVRBOOT"; type = S
    Software Version = 1.5; No Hardware Version given.
Programmer supports auto addr increment.
Programmer supports buffered memory access with buffersize=64 bytes.

Programmer supports the following devices:
    Device code: 0x76

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.00s

avrdude: Device signature = 0x1e9307
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 "main.hex"
avrdude: input file main.hex auto detected as Motorola S-Record
avrdude: writing flash (2138 bytes):

Writing | ################################################## | 100% 1.28s

avrdude: 2138 bytes of flash written
avrdude: verifying flash memory against main.hex:
avrdude: load data flash data from input file main.hex:
avrdude: input file main.hex auto detected as Motorola S-Record
avrdude: input file main.hex contains 2138 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 1.17s

avrdude: verifying ...
avrdude: verification error, first mismatch at byte 0x0000
         0x12 != 0xff
avrdude: verification error; content mismatch

avrdude done.  Thank you.

-- 
Matthew Fornero
address@hidden
(734)-846-4968