Electronics design

1. Weekly Brief Summary

This week, I designed the board using “EAGLE” based on the sample data of “echo hello-world board”.
I cut the board I created with “SRM-20”.
The board that was created was programmed using FabTiny and tested using “multimeter” and “oscilloscope”.

2. Weekly Assignment Requirement

Group Assignment

  • Use the test equipment in your lab to observe the operation of a microcontroller circuit board (in minimum, check operating voltage on the board with multimeter or voltmeter and use oscilloscope to check noise of operating voltage and interpret a data signal)
  • document your work (in a group or individually)

Individual Assignments

  • Redraw one of the echo hello-world boards or something equivalent, add (at least) a button and LED (with current-limiting resistor) or equivalent input and output, check the design rules, make it, test it.

Learning outcomes

  • Select and use software for circuit board design
  • Demonstrate workflows used in circuit board design

Have you

  • linked to the group assignment page
  • Documented what you have learned in electronics design
  • Explained problems and how you fixed them, if you make a board and it doesn’t work; fix the board (with jumper wires etc) until it does work.
  • Included original design files (Eagle, KiCad, - whatever)
  • Included a ‘hero shot’ of your board
  • Loaded a program and tested if your board works

Kamakura Group Assignment Week06

4. Assignment Work Planning

  • Group Assignment
    Verifying Microcontroller Circuit Board Operation
    (a)Using Multimeter・・・Toshiki Tsuchiyama
    (b)Verifying TX/RX Using Oscilloscope・・・Yuki Oka
    (c)Checking the Crystal Resonator・・・Hideo Oguri

  • Individual Assignments
    (a)Redesign “echo hello-world board”
    (b)Download & Use EAGLE
    (c)Cut board with SRM-20
    (d)Programming with FabTiny

5. Description of Assignment Work

Redesign “echo hello-world board” with EAGLE

① Download EAGLE

This time I used EAGLE to design the board.

download here

Downloaded the library “fab.lbr” for use with Fab Academy.

download here

② Decide Which Part to Use

echo hello-world board
micro controller ATTiny44 × 1
resonator 20 MHz × 1
capacitor 1 μF × 1
resistor 10 kΩ × 1
header 6 pin for FTDI × 1
header 6 pin for ISP × 1

＋

LED + Switch
LED RED × 1
resonator 499 Ω × 1
switch tact × 1
resistor 10 kΩ × 1

③ Use EAGLE

⑴ Project Creation

Projects ー New Project ー ” hello echo board ” ー Schematic

⑵ Add Parts

⑶ How to Find Parts Quickly

・Managed Libraries → Use none

・”supply1.lbr” → libraries

・When searching for parts, add ” * “
※ Select what the picture will be displayed in the preview.

⑷ Use ” Line tools ” to Create Schematics

While looking at ” ② Decide Which Part to Use “, arrange the parts and connect the circuits with a line tool.

⑸ Checking by ERC

Use the ” ERC ” to check for electrical connectivity issues.
This time, [1] misspelling of button, [2] Delete lines of CTS and RTS.

⑹ Board Diagram Creation

After the circuit diagram is created, the board diagram is created.
The part diagram and lines created by the circuit diagram are displayed as pictures.

Place all the parts in the frame

・place crystals near a microcomputer
・Place capacitors near microcomputers, VCC, GND ・Increase the VCC and GND lines slightly to reduce Resistor.

I did not use the [autoroute] function this time. I didn’t use [autoroute] this time because while it’s convenient, it’s not easy to use when you want to make the board as small as possible or when you want to make the placement more beautiful. So I created the pattern manually.

With the [Move] icon selected, we clicked on the part to be moved, moved it and then clicked again to place it. You can rotate the part by right-clicking while the part is selected.

Set the unit of measurement in [mm] for moving the frame line by clicking the Grid button in the upper left corner.

After placing the components, use the [Route Airwire] to connect the components together.

Before that, I clicked the Grid button and changed the unit to inches to set the solid color. Then I set the width of the solid color to [0.016] and connected the wires.

This time, unlike [Board A], the width of the solid bars connected to the power supply such as GND and VCC is set to [0.032] inch. This treatment is to make the resistor value low.

↓

⑺ Checking by DRC

Use the ” DRC ” to check whether the board is designed in accordance with the design rules of the board manufacture, such as the spacing between the wires.

⑻ Export PNG file

Prepare to write down the boards you created in Mods.
Set resolution to ” 800dpi ” and color to ” monochrome “.

When I output the created data as a ” PNG file “, the Mods size is different from the actual size.

⑼ Circuit Diagram Output Using ” Adobe Illustrator “

I wrote it in dxf file, edited it in Adobe Illustrator, and then printed it to a png file.

Same ー Stroke Color ー Path ー Outline Stroke

Trace data and outline data are created in monochrome.

Trace data

outline data

File ー Export ー Export As ー Set the resolution to 800dpi.

When I read the PNG file created in Mods, there was no problem with the expected output size.

④ Cutting with SRM-20

⑤ Soldering

Prepare the parts needed to make FabTiny.
Putting together the names of the parts, the place to fix them, and the actual things in the notebook is very efficient.

↓

⑥ Debuging

After soldering, I used a Multimer to check the current flow.
Prepare to write a program without any problems.

Using FabISP board I created at week#5, I programed the echo hello-board.

  • Connect Mac usb port and 6pin header using FTDI/USB serial converter cable
  • Connect Mac usb port and 6pin isp header using usb cableb

Connect the boards like this picture.

⑵ Programming

Create a “hello_echo” folder home and write and save the “echo.c” and “echo.c.make” code to Visual Studio Code.

Start the terminal and enter the following commands:

  • make -f hello.hello.ftdi.44.echo.make
  • make -f hello.hello.ftdi.44.echo.make program-avrisp2-fuses
  • make -f hello.hello.ftdi.44.echo.make program-avrisp2

↓

However, it became an error.

⑶ Re-Soldering

Corrected the following parts.

  • resonator portion
  • solder between PB0 and PBA

↓

The error changed, but the program could not be written.

⑷ Review Mods Preview

When I checked the preview of Mods, I found that there was no part that needed to be cut.

⇅

So I tried to use a vacuum heat gun to remove and fix the microcomputer.

↓

However, when I removed the micro-computer, I also removed the copper foil.

⑸ Modify Board Diagrams

I corrected the board diagram using Adobe Illustrator and created trace data in Mods again.
I slightly increased the width of the line that was broken last time.

I checked the preview of Mods and found that the drill is firmly seated.

⑹ Cutting & Soldering

And when I checked for electricity, the LED glittered where it shouldn’t.

When I checked the preview of Mods again, the circuit of the microcomputer part was connected.

So I used a different heat gun and removed the microcomputer.
was able to peel it off well this time.

⑺ Circuit Fixes and Re-Soldering

There were three places where there were no drills in the micro-computer part pattern.
Actually, this part was cut at the first cutting.
I removed this part with an ultrasonic cutter and soldered it.

↓

⑻ 2nd Programming

I tried programming again, and it was successful.

⑦ Validation of Echo by Arduino

Finally, I tested the echoes, and there was a problem here as well.
That’s because the my Mac doesn’t recognize the FTDI cable.（Mac OS is Catalina.）

Some Macs seem to have the ability to recognize FTDI cables.
However, I heard that there is a problem that this function doesn’t work well in Catalina.

So I installed a driver to load the FTDI cable from an external site.

Virtual COM Port Drivers
download here

D2XX Direct Drivers
download here

D3XX Direct Drivers
download here

As a result, Arduino was able to recognize the FTDI cable and confirmed that there was no problem testing the echo.

Then echo’s reaction was confirmed.

6. Description of Important Weekly Learning Outcome

This time, I could not confirm that the drill was passed by closely observing the pattern and preview of Mods designed.
I will improve next time.
As a 2nd spiral, I want to turn on LED for checking current.

8. Appendix

None