electronic design

Learn basic electronic rules

now in progress

design

I used eagle to design the board. I add only one LED(and resistor) and one button.

shematic

I draw the schematic. This is first time to draw schematic, so I reference fabAcademy tutorial. First, I Add the fab library.Then,start.

I added devices and symbols(like GND and vcc).click add button > choose component > rotate (right click) > put it (left click)

And we can also ratate by rotate tool.As per the resonators datasheet, resonator's No.2 pin is GND. In shematics, GND should be written at bottom. So I rotated resonator synbol like below image.

Next, I connected with line(NET).By Click net button and draw line to device foot from another device foot. For example, attiny's No.3 pin and No.2 pin is XTAL, so I connect it to resonaator (crystal).

And We can connect with name. click label button > click line > name. The same name line will connect.

At last,I added names and values. It is not to simulate (values do not effect to anything),but to understand which symbol is which component when we look board window.

board

Next, I arrange components layout. I am not good at soldering, and I heard it is difficult to mill thick line by our lab milling machine, so I made my board layout with margin. In order to make margin I used 0ohm resistor as jumper and I escaped the line outside.


I moved and rotate each components to proper place.


I connected these components mamnualy without cross lines by route tool. I set line width 0.4064. And I draw out line by line tool. It need margin over 2.6 mm, over 3.8mm is safe to mill (When I use 1.0mm drill for cut outline).


Also we cn use autoroute tool.(this time I did not use)


Then export. adjust the window to fit out line(interior) > select layers only No.1,16,17,18


export > image > check monochrome >set dpi 500 >set size "window">OK


At last, export interior. Do not change window size since when we exported trace! select layer only No.20.Then export. The setting of export is same as trace.


trace


interior

milling

first try

I used 0.7mm drill, so I set fab module's drill diameter 0.7, but it is too big so details can not be milled.

second try

Then I change "drill diameter" setting to 0.4 (drill remains 0.7mm).And I used 1.0mm drill for interior.

Then succeed!

built board

components

soldering

It was easier than my fab isp. I think I got used to soldering a bit and this board layout is good for beginner .

Attention point is direction of LED and button. LED's color line is cathode. Button need to confirm its datasheet.

test and programing

I test my board by a digital multimeter to find short and confirm connection. Then I connected it to may computer by AVR markⅡ and FTDI serial connection module MM-FT232.(My Fab isp can not be used. It maybe broke.)Then green light shone.

Attention point is pin correspondence between pin header and FTDI.GND to GND,CTS to CTS.I could confirm it by my board image of eagle, but it is not useful, so next time I want to write pin name to on board(now I wrote it back of board by hands).

Next I tried to write "hallo echo.c" by terminal, but fail.

I downloaded "hello.ftdi.44.echo.c" and "hello.ftdi.44.echo.c.make"and put to into same folder.

Then type $ make -f hello.ftdi.44.echo.c.make .Then I had error massage.(I miss screenshot).

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