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User avatar
By LWitter
#204532
How do I run the MiniGen board in stand-alone mode? This is advertised on the website as a possibility "Though the MiniGen is technically a shield it can, in fact, operate as a stand-alone board capable of the the same functionality as it would if it were placed on top of a Pro Mini." But I can't seem to figure out how to do it.

I hope someone can help me with this!
User avatar
By TS-Chris
#204549
Hello, and thanks for your post!

You can use the MiniGen like any other breakout board but you're going to want to use it with 3.3 volt logic. You will either need a 3.3 volt micro controller or use a logic level shifter if you have a 5 volt micro controller that has 5 volt I/O.

The diagram below is how you would use it as a breakout board.
11420-03.jpg
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User avatar
By LWitter
#204551
Wait a second, your definition of a 'stand-alone board' is that it is connected to a microcontroller, just not necessarily on top of it (like a shield)?

Do you always need to provide the SCLK, SDATA and FSYNC in addition to the 3.3V and Ground? In that case it would be hard to argue that this is a stand-alone board. Merriam-Webster defines stand-alone as 'Self-contained' or 'operating or capable of operating independently of a computer system' which certainly is not the case when the board always has to be connected to a microcontroller.
#204554
your definition of a 'stand-alone board' is that it is connected to a microcontroller, just not necessarily on top of it (like a shield)?
Correct, that's what we mean but 'stand-alone board' in this context. The MiniGen by itself can't function without being told what to do. It's like a PC without an operating system. You need software to instruct the PC how to work.
Do you always need to provide the SCLK, SDATA and FSYNC in addition to the 3.3V and Ground?
Yes, that's how you deliver instructions to the board. Without instructions, the MiniGen will just sit there and light up a power LED.
User avatar
By LWitter
#204585
I'm sorry to bring you this, but you can't change the definition of a word to fit your needs. Stand-alone should mean that it can be used without a microcontroller. So, program and use as a separate entity.

So, I can conclude that I have bought a sound board that was advertised as a stand-alone board, but really isn't. Furthermore, it doesn't directly out of the box works with an Arduino because of the sensitivity to noise, AND that the level shifter you sell is actually not really working.
To get the minigen programmed I had to resort to using a CD4050 and throw out your Level Converter, only to discover that the minigen is also useless!

Shame on you!
By n1ist
#204594
While I agree that "stand alone" can be misinterpreted, if you look at the schematic and datasheet for the AD9837 (both available under the documentation tab on the MiniGen SparkFun page), it is very clear that this needs a processor or similar to configure the AD9837. As for working with an Arduino, it will work directly with any 3.3V Arduino. I am not sure what the issue you had with the level shifter was (you just complained about it in the last post, and didn't include any descriptions on what wasn't working with it, or pictures of how you hooked it up) but I have used the level shifter many times in the past with no issues. Given that this is a SPI slave, you could have just used voltage dividers to do the level shifting.

/mike
User avatar
By LWitter
#204601
My previous response this was worded too strongly, my apologies. I should not write posts when angry and frustrated.
Still, I think a company like sparkfun (who I think targets the 'fun' in electronics) should not require their customers to go through datasheets to see whether claims on the website are correct. I came to the CD4050 after a suggestion from a colleague and your colleague. I have extremely limited understanding of electronics. Asking me to go through a datasheet for these things is like asking car buyers to go through the engine specs, weight and drag coefficients to calculate probable top speed of the car. When a car manufacturer claims a top speed and it is off my miles an hour we would all agree it would be false advertising, even though with the correct background I might have noticed something off.

In my previous post your tech support colleague also agreed that there was an issue with the minigen board in combination with the level shifter, so there is more going on than you might think.

I'm disappointed in the minigen board. It really is not what I need and I bought it because of the claims on your website.
By n1ist
#204606
I had missed your other thread on this topic. Just to clear up one point, I don't work for Sparkfun; I am just a customer like you.

The CD4050 is a valid way of doing level shifting. As for the issue with the FET-based level shifter, I wonder if the issue is due to the setup and hold timing between SCLK and FSYNC. Putting both on the scope at once and looking closely at the edges of FSYNC would show if this is the issue.

I view most of the boards from Sparkfun as breakout boards; as such, I look at the datasheets and the example code to figure out how things work.
/mike