(5) And yet it moves - part 2

It took a while to get to write this page because setting up the Sanguinololu electronics was a painful process.
If I will build another printer I will choose a more beaten path - Arduino Mega with Ramps and motor drivers.

I shortly realized that there is no bootloader on the Sanguinololu's Atmega1284p, so I bought a $7 USBasp programmer from ebay. I tried to follow the instructions from USBasp programmer for Sanguinololu page, but no success. You can see my setup below (NOTE: Do Not power the Sanguinololu board, the chip will be powered by the programmer)

My patch between the programmer and the Sanguinololu was:

Function	USBasp Programmer Output	Sanguinololu ISP header
MISO	9	1
VCC +5V	2	2
SCK	7	3
MOSI	1	4
RESET	5	5
GDN	10	6

After I exhausted all options that I could think about I decided to buy a Arduino Uno to use it as a programmer and use the approach from this Burning the Sanguino Bootloader using Arduino as ISP page, but patching to the Sanguinololu board directly, because I did not have all the electronic components, using the following patch table:

Function	Arduino UNO Pins	Sanguinololu ISP header
MISO	12	1
VCC +5V	5Vcc	2
SCK	13	3
MOSI	11	4
RESET	10	5
GDN	GDN	6

And you can see my new setup:

This din not work either.

I decided to go all the way, remove the Atmega chip and program it on a breadboard. When I removed the chip I noticed that the 16MHz ceramic resonator was chipped with the pins bent under the Atmega microcontroller.

I ordered the components on ebay, replaced the ceramic resonator, but still went with the breadboard. I ended up with this setup:

This time it worked and I successfully burned the bootloader from the Marlin firmware on the chip using the burn bootloader option in Arduino IDE. For more details check Steve's blog about building Sanguinololu board. 

I learned next that the default fuse settings from the boards.txt file did not match my board case and used this Fuse Calculator to set my values. In my case I used:

• Low Fuse:        0xE6
• High Fuse:        0xDA
• Extended Fuse: 0xFD

To burn the fuse settings with the Arduino as ISP I used:

avrdude -p m1284p -c arduino -P com3 -v -b 19200 -U hfuse:w:0xDA:m -U lfuse:w:0xE6:m -U efuse:w:0xFD:m

In the end I modified the Sanguinololu entry in the boards.txt file to reflect my fuse settings:

atmega1284.name=Sanguinololu W/ ATmega1284p 16mhz

atmega1284.upload.protocol=stk500v1

atmega1284.upload.maximum_size=129024

atmega1284.upload.speed=57600

atmega1284.bootloader.low_fuses=0xE6

atmega1284.bootloader.high_fuses=0xDA

atmega1284.bootloader.extended_fuses=0xFD

atmega1284.bootloader.path=standard

atmega1284.bootloader.file=ATmegaBOOT_1284P.hex

atmega1284.bootloader.unlock_bits=0x3F

atmega1284.bootloader.lock_bits=0x0F

atmega1284.build.mcu=atmega1284p

atmega1284.build.f_cpu=16000000L

atmega1284.build.core=arduino

With the bootloader in place I opened the Marlin.ino file in the Arduino IDE, compiled and load it onto the board.
I used both controlling software (Repetier Host and Printrun with Pronterface) on a windows 7 PC and send manual commands to start moving the motors and finally got movement.
In the next post I will show the assembly of the extruder and attachment of the hot-end, plus wiring all together.