|Use the test equipment in your lab to observe the operation of a microcontroller circuit board|
|check operating voltage||Yes|
|use oscilloscope to check noise of operating voltage||Yes|
|use oscilloscope to interpret a data signal||Yes|
|document your work (in a group or individually)||Yes|
Check Board with Oscilloscope¶
By Dan Meyer
I used the SparkFun Electronics How to Use an Oscilloscope video to get me started with the Oscilloscope I have. I have never really used an Oscilloscope before, but I have seen others use one and understand the basic reason for using one. Specifically helpful for me to learn my Tektronix TDS 1002 oscilloscope are these documents: Really great video to help me learn all the knobs and buttons: Tektronix Oscilloscope Tutorial Part 1 The original manual for my model of oscilloscope was great too!: TDS1000- and TDS2000-Series Digital Storage Oscilloscope hosted by Neurophysics Lab at UC San Diego
Lab power supply at 5vdc
Leads for 5vdc test
Check noise of operating voltage¶
O-scope reading of 5vdc from lab power supply, at this point I have learned how to zoom in on curves and move horz and vert. I am very zoomed in at 200mV per grid.
Let’s try and see if the 5vdc from this xtar 18650 USB power bank look any different.
Yep it looks different, a little wider 5vdc sweep, but not much more sweep at all, I am very zoomed in at 200mV per grid.
Let’s try measuring this point just after the ORG LED.
Here is the reading, I learned how to move cursor at this point. The reading is 3.28V at the cursor. What’s the voltage on the pin 2 of the MCU?
Here I learned how to move two cursors and I zoomed in to 100mV per grid section. Delta is 252mV, Max 2.92V Min 2.66V
Let’s measure the voltage at this pad on the USB Delta is 224mV, Max 2.90V Min 2.68V
Interpret a data signal¶
I just purchased the low cost $180 Miniware DS213 Oscilloscope for our Fab Lab. This is my first time measuring signals on an Oscilloscope, let’s see what happens! I watched the video Tutorial. DS213 Oscilloscope to learn.
Ground and probes connected LEDuo board.
Probing LED outputs.
I set the CHA and CHB to DC, and the horizontal grid to 0.2V for both channels. I moved CHA and B to a point in the middle bottom of the horizontal trigger line. I changed the vertical grid to 50ms
In the photo above you can see Channel B (Yellow Line) TwH (Time Width High) is 20.0ms, this means the LED on Channel B is on for 20.0 ms.
In the photo above you can see Channel B (Yellow Line) TwL (Time Width Low) is 20.0ms, this means the LED on Channel B is off for 20.0 ms.
In the photo above you can see Channel A (Blue Line) TwL (Time Width Low) is 240 ms, this means the LED on Channel A is off for 240 ms.
In the photo above you can see Channel A (Blue Line) TwH (Time Width High) is 40 ms, this means the LED on Channel A is on for 40 ms.
Using the Oscilloscope is a great way to check to see if the code I loaded on my board is doing what it was commanded in the real world.
The Miniware DS213 Oscilloscope works great! Also it’s limited options makes it less intimidating than more featured packed Oscilloscope.