There are ancillary features in my synthesizer design which will not be discussed here. Once you get the critical parts of the system working you will presumably be capable of designing and implementing further features as you like.
You will also find other literature online of similar projects with different microcontrollers from which you can adopt the theory. Personally I found the early stages of development most challenging, so that is what I will focus on. How exactly you approach this project is going to be based largely on your intentions for the finished product i. USB interfacing? Analog effects?
This is your time to do the trades and preliminary research to determine what is feasible for you. Read all available datasheets like a madman and compile as much reference material as you can in your project notes. Most parts can be ordered online through suppliers such as Mouser or Digi-Key, but the keyboard is somewhat unique and I suggest you source one from a relatively cheap electronic keyboard and then design everything around that.
I recommend that you order more parts than you need and be able to reuse them later, rather than find yourself short one and unable to continue. Whenever possible order enough parts to make two complete projects in parallel; it makes the debugging stage go much quicker. Also be aware of bulk discounts. You may only need six capacitors at 30 cents each, but if you get ten the unit price could drop to 15 cents each.
There are two major types of keyboards you can expect to find polyphonic and monophonic , depending on how much expense was spent in manufacturing, but they will be interfaced in roughly the same way. The vast majority of keyboards use what is referred to as a " switching matrix ". In short, the keys are mapped out on a two-dimensional plane where each key has its own row, column coordinate. What I mean by "polyphonic" and "monophonic" in this context is whether or not the columns are isolated sufficiently at the hardware level to where you can press more than one key without "ghosting".
This gets beyond the scope of the instructable, but please do look it up if you are interested. You may also encounter "velocity sensitive" keyboards; these will have two coordinates per key and you can either wire one or wire both if you want to support the velocity sensitive functionality. The accompanying code on your microcontroller will have to account for this of course. When you find a keyboard to source for your project, look for the flat ribbon cable connecting it to its original control circuitry.
Those conductors are the rows and columns which you will interface with your controller board. In order to map out their location, you will need to either follow the traces by eye or press a key and find a short between rows and columns with a multimeter.
Make a table in your notes for this project which maps these coordinates to the musical notes. Usually we center the keyboard at octaves 0 and 1. If you intend to make your own original enclosure, start by measuring the dimensions of the keyboard and looking for ways to interface it with the rest of your enclosure. This is most often done by adapting the original mounting brackets, and you may even be able to reuse mounting hardware.
Depending on what kind of ancillary features you plan to include, you want to consider different kinds of control panel layouts. I recommend that you make enough room for the most complicated control panel you could possibly populate, but not drill any holes for mounting components to the control panel until the entire panel is finalized.
This usually cannot be easily reworked, so make sure you know what you want beforehand. Revisit the control panel after your circuit has been designed and your working board is ready to be installed. I feel that there are too many variables which you can't account for and interfaces you can't imagine if you are not handling and working with the parts in person.
I did model this project and ended up redoing every interface at least twice, not to mention several complete revisions which did not pan out due to various circumstances. When designing the enclosure it's better to be aware of what you have available, so think of what you want to make and then go to the hardware store and see what they have to make it happen. Perhaps you want a 4x12" control panel, but you can find a 6x18" sheet at the store; adapt your design to reduce the amount of custom parts you need.
Once again, it's also better to buy more than you need and return it or end up one short, so keep that in mind. Old thread, but I'm about to start a similar project with an SNAN, and I've read in the specs, that the data to be latched into its registers must be present for at least 32 clocks 8 clocks for N - suppose. The READY line is open-collector and must be pulled-up by an external resistor anything is fine in the range of 1kk. It seems you have to connect the data lines reversed.
I'm a bit mixed, I've never read any reference to it on other sites. I have to check it manually EDIT: other sites claims the data pins reversed already compared to what I linked.
That makes sense. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Asked 4 years, 7 months ago. Active 2 years, 11 months ago. Viewed times. Thank you Will Thanks to everyone, especially Tony Stewart. Dave Tweed k 16 16 gold badges silver badges bronze badges. So you need to buffer it with a transistor. Use a base current-limit resistor of 5 k or so, since the low output max current is rated for 2 mA.
As others have said - ensure loading capabilities are known and nor exceeded. Rise and fall times are unlikely to be the problem but ensure they are "sensible". Add a comment. Active Oldest Votes. I understand most of what you are saying although I do not understand all of it which is fine.
I can figure out most of what I don't understand by trying it out. Jun 21 There is no relevant information available for this part yet. The SNAN components of Apogeeweb Electronics are carefully chosen, undergo stringent quality control, and are successfully meet all required standards. The production status marked on Apogeeweb. If you did not find what you were looking for, you can get more value information by email, such as the SNAN Inventory quantity, preferential price, and manufacturer.
We are always happy to hear from you so feel free to contact us. SNN with pin details manufactured by TI. Irene 23 Sep The SN is characterized for catalogue operation.
Continue reading ». Irene 15 Sep Each output is disabled when the associated output-enable OE or input is high Irene 29 Sep
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