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7. Electronics design

This week we worked on using the test equipment in our lab to observe the operation of a microcontroller circuit board.

Test equipment

Test

In this week, we worked for redrawing the echo hello-world board, addinng a button and LED (with current-limiting resistor), checking the design rules, making it, and testing it. As the result of indivisual project, we got the board.

The board

In order to observe the operation of a microcontroller circuit board, we connect it to MacBook and to oscilloscope. This time we used an oscilloscope called Tektronix TBS 1052B.

Tektronix TBS 1052B

We inserted a pinheader between MacBook and oscilloscope to capture signals to and from the board.

Pinheader

At first, we wired GND and TX with Ch1, and GND and RX with Ch2.

Then opened Terminal and run the code below.

python term.py /dev/tty.usbserial-FT9OZSKA 115200

If we successed, dialog showed up.

Dialog

Pushed run button on osiclloscope.

Run button

Then typed a letter and saw the result.

First result

1 vertical grid equals to 2V and horizontal grit is time. By the result, it seemed Ch2 responded but there was no response on Ch1. This meant it detected the signal we sent but didn’t captured the returned signal.

Response

So we swapped RX and TX. As the result of it, we got responce both Ch1 and Ch2. This mean the board communicated with Macbook and we detected it correctly.