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An Arduino compatible shield matched with a web based tutorial system to teach you how to talk with I2C and SPI components.
An Arduino compatible shield matched with a web based tutorial system to teach you how to talk with I2C and SPI components.
101 backers pledged $10,045 to help bring this project to life.

Strategic Investment...

Posted by Daniel Hienzsch (Creator)

Hello everyone, I hope your weekend is off to a good start.

In preparation for the upcoming material I'll be producing for this course, I thought it wise to investment in improved test and measurement equipment here at the lab.  Back-orders and manufacturing delays finally all resolved themselves, and this week saw the addition of the two most important pieces for the I2C and SPI Education System. (If you're following @rheingoldheavy on twitter, then the surprise is already spoiled)...

Rigol DS1054Z Four Channel Oscilloscope...

I purchased the DS1054Z for a pair of reasons: 1. it features a vastly improved display over the DS1102E that I've been using for a year now and 2. it has four input channels.  Troubleshooting SPI design when you only have two channels to work with can be tricky and involves swapping your test leads back and forth and reconfiguring your triggers. This will hopefully make any troubleshooting that I have to do in the test phase of production that much faster, even though I think we all hope there isn't much troubleshooting at all during testing.

When you have all four channels humming, you can do some pretty cool things...

That's showing a full decoding of a single SPI communications stream.  The problem with an oscilloscope though, is that it's impossible to really interact with that data in more than just single chunks of data, particularly since you have to twiddle the buttons and knobs to zoom in and out and grab the correct timing and triggers (in addition, I'm only able to get the decoded values because Rigol supplies a 35 day demo license on that feature, after that, it's an extra $200). 

If only there was a tool specifically for working with serial communications!!!

Saleae Logic 8 Logic Analyzer...

We're going to be checking and analyzing serial communications, and this will really help us visualize what's going on in a very clean fashion.  The oscilloscope can help you to verify that your signaling configuration is correct, but if you want to see what's occurring over a time period rather than a single communications frame, then you need a logic analyzer, which records and interprets the serial stream over a time length you specify.

For example, here's a SPI signal captured over 2.5 seconds.  Everyone one of those tick marks, is an entire chunk of data coming back

 The Saleae allows you to zoom in on any of those tick marks to see what is going on inside...

With these tools at my disposal, you should expect to see quite a lot of that sort of material in the modules I'll be producing.  Both the Saleae and the Rigol allow export of data in csv format as well, so I'll be able to share the captured data with you in a more interactive fashion than just screen captures.

In project news, the $5000 threshold was crossed!  It's typical for there to be a lull in new backers for a technical project like this in the middle period, so I expect slow progression this upcoming week up to the typical mid-month pay period here in the United States, when there may be another bit of a bump up.

Tomorrow I'll provide an update on the final production design progress.

Thank you again to everyone that has backed this project so far.  As always, feel free to reach out to me with any questions you have.

-dan

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