The assignment for this week was to make the FabISP (In-system programming). The FabISP is an in-system programmer for AVR microcontrollers, that allows you to program the microcontrollers on other boards using a USB cable and 6-pin IDC to 6-pin IDC cable. We will be using these programmers through the semester to program the other boards we create.

It was the first time I "touched" concretely the argument "electronic".I was a bit scared, but it's over when I started to work.

I made the ISP from a copper plate using the Roland monoFab SRM-20 milling machine.

Procedure:

- Download the Board Files; hello.ISP.44.traces.png and hello.ISP.44.interior.png;

- I generated the gcode .rml files (this is the format that Roland monoFab SRM-20 milling machine reads) using the FABModules an online software create by Fiore Basile in Fab Academy 2014;

- Open fabmodules.org;

- Push on Input Format;

- Choose Image(.png) and Upload Image;

- Push on Output Format and choose the machine (Roland Mill (.rml));

- Setting machine: machine SRM-20; Xmin 0; Ymin 0;

- Push on Process and choose (PCB traces(1/64) or (PCB outline(1/32);

- Change offset 5 (the offset is a personal setting);

- Push on Calculate;

- Save;

- If the machine is turn off for a long time, turn on the machine for the heating, at least for 15/20 minutes;

- When the machine is ready, mount the tool on the machine and setting the milling coordinates in the Vpanel software on the terminal: first the XY axes then the Z one.;

-start to mill the hello.ISP.44.traces.rml file using the tool 1/64 size;

-change the tool with a tool 1/32 size in order to cut the hello.ISP.44.interior.rml;

After finishing the milling process I had to solder the components on the board.

Components:

- 1 ATTiny 44 microcontroller

- 1 Capacitor 1uF

- 2 Capacitor 10 pF

- 2 Resistor 100 ohm

- 1 Resistor 499 ohm

- 1 Resistor 1K ohm

- 1 Resistor 10K

- one 6 pin header

- 1 USB connector

- 2 jumpers - 0 ohm resistors

- 1 Cystal 20MHz

- two Zener Diode 3.3 V

- one usb mini cable

- one ribbon cable

- two 6 pin connectors

It was the first time I try to solder. After this experience I realized that I need a lot of training, but in the end I did it: I soldered my first PBC.

Very important thing to do is to always test each component and trace, using the tester to avoid that there are contacts or short circuits.

I used USBasp - USB programmer for Atmel AVR controllers to program the microcontroller ATtiny44A of FabISP.

For this reason I had to change a line in the Makefile to tell to the system to use usbasp: AVRDUDE = avrdude -c usbasp -p $(DEVICE) # edit this line for your programmer.

To start I need to have Softwares dependencies and Firmware installed (in my case I used Operating Sysem Ubuntu):

- Open Terminal and type: sudo apt-get install flex byacc bison gcc libusb-dev avrdude

- Then type: sudo apt-get install gcc-avr

- Type "y" when asked to do so by your system

- Then type: sudo apt-get install avr-libc

-Then type (may already be installed): sudo apt-get install libc6-dev

-Move to the desktop: cd ~/Desktop

-Download the firmware from the Fab Academy Electronics Production page: wget http://academy.cba.mit.edu/classes/embedded_programming/firmware.zip

-Unzip the firmware: unzip firmware.zip

To program the ISP I followed this Tutorial

I programmed FabISP as shown in the tutorial, but I had a lot of problems: the computer did not recognize the programmer. I tried again a few times and I realized that the computer occasionally receiving a signal. The usb mini had a problem of contact, could not keep constantly the connection. I stuck the usb mini with a little hot glue and I added a USB adapter. In this way I solved the problem.

Steps to programming the microcontroller of Fab ISP:

- Type: cd Scrivania/firmware;

- Compiling the firmware. Type: make clean ;

- Then type: make hex ;

- Setting the fuses. Type: make fuse ;

- Programming the board. Then type: make program ;

Remove the 0 ohm resistor and solder bridge to use the programmer

Download Files