Subject: Re: [linux-audio-dev] MIDI-controllers?
From: David Olofson (david_AT_gardena.net)
Date: Fri Mar 17 2000 - 22:29:18 EST
On Fri, 17 Mar 2000, Juhana Sadeharju wrote:
> Hello and thanks for the controller tips. I have downloaded punch of
> documents and will look around for controllel and chip manufacturers.
>
> None of controllers what I have seen does entirely satisfy me.
What are you looknig for? As for price/performance and availability
of development tools, it's probably hard to beat the PIC and 80C51
families.
Atmel makes very low cost 80C51 compatibles with flash, fast mul and
div and clock rates up to 24 MHz. I don't remeber all figures, but I
think you can get versions with up to 64 kB flash, a few kB RAM
and/or external bus. (The normal ones have only ports.) You can get
one running with only power and an oscillator... (Actually, you can
leave out the oscillator as well, as there is a built-in ceramic
resonator that generates a 1 MHz clock or something like that.)
As for C51 being fun - naah... Old, old stuff. Atmel made them usable
by increasing the clock rate (an instruction cycle is 12 clock
cycles!!!), but there are MCUs with more exciting specs. They're
usually orders of magnitude more expensive, though.
Another important part of the problem is that you need a development
system as well. A good one costs around $10,000 - $50,000 depending
on target chips supported (hardware emulation is *very* complicated
at high speeds), but there are evaluation kits and simple development
systems that let you do quite a lot.
Equinoxe Technologies has a little kit for the C51 chips, but
unfortunately the software is restricted to 2 kB (IIRC) of code. (The
full version is unlimited of course, but I don't know how much the
upgrade is.) Anyway, this kit is based on software simulation first,
then flash + test in-cirquit. No emulator, that is. The simulator
lets you run the code on a virtual C51, and you can simulate the
external hardware using a C-like scripting language. It's possible to
have the chips accept software download to the flash in-cirquit.
I've thought about looking for some Free tools that can be used with
these MCUs, but I haven't got around to it yet. I think I've seen a
gcc for 80C51 though...
> I'm looking in if I'm able to build a partial prototype of my ideas.
> That's like "how to become a digital electronics designer in a week" ;-)
Well, if you want to get away easy, you should probably look up some
MCU with most of what you need (AD/DA, timers,...) built-in, so that
you don't have to build and debug all that much hardware.
If you want to test the actual sensors, algorithms etc before
building an MCU based implementation, you could connect the hardware
to a PC (parallel port or some lab/prototyping I/O card) and use the
normal development tools. There is RTLinux if you need µs range
response times - pretty easy to program (easier than DOS, I think,
and you have Linux around for non- and soft RT stuff), but it
doesn't have protected memory.
//David
.- M u C o S --------------------------------. .- David Olofson ------.
| A Free/Open Multimedia | | Audio Hacker |
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`------------> http://www.linuxdj.com/mucos -' | Open Source Advocate |
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