[sdiy] microcontroller selection!
clone45 at hotmail.com
Fri Aug 8 22:59:46 CEST 2003
[ This question is unrelated to my question on the sampler module. ]
I just completed a prototype of a Doepfer compatible module that uses the
OOPic microcontroller. The module is a generic - programmable module for
logic function. It can do sequencing, clock division, pattern generation,
etc. I'm working on a website that shows it off, so I'll have a demo soon.
I'd love to sell it soon and share the joy! ( I may start my own business
making music gear!! Woop! )
In any case, now that it's finished, I've found that there are some speed
issues. Especially when doing a/d conversion. The module is quite
functional and fun, but there's a small delay between the time that you
clock it to when it produces output. BEST case (very rare), is a nearly
instantaneous response... but that's the simplest function programmed in the
fastest way possible (using virtual circuits in the oopic).
More realistic programming introduces delays ranging from 1/100th of a
second to probably much much worse. Part of the timing issues are
introduced when I do slow a/d conversion. Some timing issues exist because
the OOPIc is very slow when programmed in a traditional fashion. My module
has a serial port right on it, so users can program in their own stuff, and
they'll probably opt for the slow, easy method of programming.
Even _with_ the input to output lag, the project has been a raging success.
It's a very, very cool module. It's internally consistent, so using it as a
4 part pattern generator works great. The reason I choose the oopic is
because it's very easy to program and hooks up via a serial port. The
software to program it is free and very easy to use.
Here's my question - - - should I go with this solution, using the slow-ish
OOPic, or is it worth researching using a faster microcontroller? The basic
stamps might work better, but wouldn't I still get delays when doing a/d
conversion? Another way to look at it is... if the module is going to be
based on a programmable microcontroller, should it be *expected* to have
clock->output delays some of the time? (dependant on the programming
efficiency, etc). Obviously I'd have to make that very clear if I sold it.
I would prefer a much faster family of Amtel microcontroller, but I really
wanted to make this super easy to program, and super easy to hook up to a
computer. Even with an Amtel microcontroller, there's a chance that a/d
conversion or sloppy programming could cause small timing issues.
Thanks for your input!!
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