Bootloader Programming

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Bootloader Programming

The bootloader is a program that needs to be loaded into the ATMEGA328P before you can program your Arduino with the USB/serial programmer.

We really should have provided a programming header for that as well as the one for the USB/serial programmer, but since we didn't, the professor will program your ATMEGA328P units using the information on this web page.

On the USBtinyISP six pin header, the connections I made are: Pin 1 in brown. Pin 2 in red. Pin 3 is orange. Pin 4 is yellow. Pin 5 is green. Pin 5 is blue. The connections on the Pro Mini are from here. Programmer connections.jpg

First I need to check to see that the fuses are okay, and that the USBtinyISP will work.

$ avrdude -c usbtiny -p m328p

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude: Device signature = 0x1e950f

avrdude: safemode: Fuses OK

avrdude done.  Thank you.

I read the original firmware into an Intel hex file using this command below just in case the ATmegaBOOT_168_atmega328_pro_8MHz.hex file doesn't work.

$ avrdude -c usbtiny -p m328p -U flash:r:original.hex:i

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude: Device signature = 0x1e950f
avrdude: reading flash memory:

Reading | ################################################## | 100% 50.06s



avrdude: writing output file "original.hex"

avrdude: safemode: Fuses OK

avrdude done.  Thank you.


Now I programmed the ATMEGA328 using the following command: Don't do this! It turned out to be a good thing I backed up the original firmware, because though the following programmed okay, I couldn't use the serial programmer to load sketches from the Arduino IDE.

$ avrdude -c usbtiny -p m328p -U flash:w:ATmegaBOOT_168_atmega328_pro_8MHz.hex

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude: Device signature = 0x1e950f
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 "ATmegaBOOT_168_atmega328_pro_8MHz.hex"
avrdude: input file ATmegaBOOT_168_atmega328_pro_8MHz.hex auto detected as Intel Hex
avrdude: writing flash (32652 bytes):

Writing | ################################################## | 100% 68.70s



avrdude: 32652 bytes of flash written
avrdude: verifying flash memory against ATmegaBOOT_168_atmega328_pro_8MHz.hex:
avrdude: load data flash data from input file ATmegaBOOT_168_atmega328_pro_8MHz.hex:
avrdude: input file ATmegaBOOT_168_atmega328_pro_8MHz.hex auto detected as Intel Hex
avrdude: input file ATmegaBOOT_168_atmega328_pro_8MHz.hex contains 32652 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 48.37s



avrdude: verifying ...
avrdude: 32652 bytes of flash verified

avrdude: safemode: Fuses OK

avrdude done.  Thank you.

So after testing and finding this bootloader wouldn't allow programming sketches from the Arduino IDE, I flashed back the original firmware, and it worked.

$ avrdude -c usbtiny -p m328p -U flash:w:original.hex:i

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude: Device signature = 0x1e950f
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 "original.hex"
avrdude: writing flash (32670 bytes):

Writing | ################################################## | 100% 67.85s



avrdude: 32670 bytes of flash written
avrdude: verifying flash memory against original.hex:
avrdude: load data flash data from input file original.hex:
avrdude: input file original.hex contains 32670 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 49.58s



avrdude: verifying ...
avrdude: 32670 bytes of flash verified

avrdude: safemode: Fuses OK

avrdude done.  Thank you.

The next step was to unsolder the ATMEGA328P and solder in a new one to program. Sockets for these are expensive, and even if we had the budget, there is no time for any other method.