WEEK 4

ELECTRONICS PRODUCTION

Make the Fab (tiny)ISP in-circuit programmer.

Which FabISP key: Andy's one

We decided with the team to go on the Andy's FabISP key.
We went to Andy's repository on GitHub to get the last version of his key (v2.3), there we took the schema of the key (.png files).
We transformed the .png files into .dxf files using Inkscape,
then we opened them in VCarve Pro in order to build the final file (a G-code .tap file) compatible with our enormous CNC machin ;-)

Getting the source on Andy's repository:

Andy's key schemas in .png:

Creating and preparing the board

As we did not receive the desktop milling machine,
We had to use the big CNC.

A long time to get it running,
A lot of configuration, with some different milling cutters.
But finally it runs

Here is the result, not so bad
(for a PCB done with such a big CNC machine).

But using the magnifying glass
It is not so clean, and we need to manually arrange this...

after some time, using sandpaper, and a cutter,
the PCB is no more presentable.

connection are tested using a multimeter
and holes are done for 2 componants that will require it.

Starting soldering of components

Using some pliers and Kapton Tape in order to maintain the componant at its good position.

Using Solder Paste to do the soldering

Here is the result
It looks clean

Here is our soldering installation

And around 08:00PM on tuesday we finally did some better board (using another PCB material),
probably the good board to finalize my FabISP key!

Finalizing the soldering

We use some Flux to simplify the soldering
It is really easier with it

When I tried to unsolder a connection,
I damaged my PCB, 1 trace was broken

I repaired it with a wire
and I tested with the multimeter, every connection is ok after this reparation
even with the capacitor solder on it

Here is my final FabISP
not so bad for a first soldering ;-)

Now programming it

First, I tried to program my FabISP with an Arduino Uno, but it was a failure.
Then I decided to use a USBasp as a programmer.
As a first test, I tried to read the flash of the microcontroller of my FabISP,
this was working Ok, see the result here:

Secondly, I updated the Makefile.
In a very first time with the firmware from Andy's GIThub, but it gave errors (when doing "make hex" command)
Then I did it with the firmware from the Schedule page from the FabAcademy website
Here is the change done in the Makefile, to specify the USBasp as a programmer

Here is my "make hex" command output:
test.hex file

Here is my "make fuse" command output:

Here is my "make program" command first outputs.
Giving some errors (different error each time, like random)
Very probably because of not enough power!!

Here is my "make program" command output, after connecting the FabISP to a USB port to give some additional power

Here is my FabISP visible from my OS
ready to use !! :-)
after unsoldering the 2 jumpers

Here is the USBasp programmer:

Here is my FabISP, connected to a USB concentrator, to give the extra power: