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Week 06 Electronics Design

Group assignment

  • Use the test equipment in your lab to observe the operation of a microcontroller circuit board

result -> group site

Thought and feelings

  • I learned how to use oscilloscope and when it should be used.
  • Oscilloscope is used especially for debugging;
    • To know the device is working as expected by checking Voltage and Time. For example the pulse is generated in oscilloscope but the LED is not blinking, then I know the program and the controller is ok but something wrong with the LED or cable.
    • As this oscilloscope has 4 channels I can use the checking of the combination of devices by watching 4 waves at the same time.
  • This is good start to know how to debugging.
  • Some questions are not solved yet. I will study more for coming debugging.
    • Why LOW signal was longer than programed while HIGH signal was the same as programed?
    • Why the analog wave shape was not stable or I could not adjust properly?

Individual assignment

  • Design a development board to interact and communicate with an embedded microcontroller

Result

  • I designed a board for 2 sensors and 1 sound device with Kicad.
  • Microcontroller is xiao RP2040. Schematic(original data)
    x12 PCB (original data)
    x13

Process to the result

  1. Start a new project file
    x1

  2. Add symbols I can add a new symbol by clicking "Place" -> "Add symbol"
    x2
    Automatically a window pops up
    x3
    Search by inputting Filter window
    x4
    A symbol appeared on the working sheet

    If I want to add a symbol but not included in original library, I can add it. For example, my design includes XIAP RP2040, but it was not on the original library then I refer this site and downloaded the library file.

  3. Draw lines
    I can draw line (pattern) by clicking "Place" -> "Add Wire"

    Click start and goal of the line to draw it

  4. Checking or change footprints
    Once all symbols are allocated on the sheet, I need to link the symbols and footprints by "Run footprint assignment tool" and find the appropriate footprint for each symbol.
    Once footprint is assigned, I can check it by "Right click" -> "Edit footprint"

    "Edit Footprint Field" window pops up, and I can see actual footprint


    I can choose other footprint with this window

  5. ERC (Electrical Rule Check) Once schematic design and annotation complete, I can run ERC.
    ERC detects something if the design was wrong by electrical theory of view.

  6. Update PCB from Schematic
    By clicking "Tools" -> "Update PCB from Schematic", the design changed into PCB


    Then I move symbols and draw route tracks to create actual board design
  7. Design PCB
    I need to draw cable line (tracks) by "Route tracks" tool

    I can change the track width by "right click" -> "Properties" -> "Track width"


  8. Drawing edgecut There is shape drawing tool (rectangular etc.), but important thing is to choose appropriate layer. For edgecut, I choose "Edge.Cuts" layer and draw edgecut line.

Thoughts and feelings

  • The first use of Kicad, took long hours for new tool as usual. Especially when I draw a line, it moves unexpectedly.
    kicad6
  • This time I stuck 2 times for drawing PCB.
  • At first I used horizontal connectors, it caused many cross lines so I could not draw anything. Instructor advised that if I use vertical one the connecting part is not on the board (standing) so the line can go straight for next device.
  • Still there are 2 crossing points. And this was cleared by using 0 resistors to make bridges.
  • I learnt that to make PCB simple, I need to know physical shape of connectors and other devices. And also do not hesitate using 0 resistors to make it simple.
  • At this moment I enjoyed line arranging as a puzzle, hope this feeling continues.

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