Re: Wico XY Pattern Generator - Schematic capture complete

On 11/14/2011 11:31 AM, Clay Cowgill wrote:
> >The real way to re-design this is to use a ST Micro Cortex-M3 ARM
> processor,
> > with built-in DACs, and a couple of op-amps. You could have user
> downloadable
> > patterns. Or heck, you could just throw in an emulator and run games
> directly from
> > the ARM's memory.
> For a pattern tester the ARM's even overkill (although for bang per
> buck it's hard to beat). Atmel's XMega A4's work fine for vector
> based stuff with their internal DACs. A few bucks each in small
> quantities for the 32K flash part. I made a vector generator for an
> RGB laser with three chips-- XMega32A4 and a couple TL082's-- and a
> little CUI 5V-> +/-15V DC/DC converter for the analog rails. (I used
> the ADC inputs on the micro to digitize sound and control the vector
> generator.)
I'm a big Atmel fan as well, but I've started using ARM's, and I
probably won't go back. For my needs, the ARM ended up being cheaper
than the XMega series. TI has parts with the Ethernet mac AND phy built
in (all you have to do is connected the pins to a RJ45 connector with
built in magnetics, throw in some firmware, and you're on the net!).

I only went with ARM because Atmel kind of screwed me on the
ATXmega256A1. I had a datasheet, and an assurance from a factory rep
that it was coming soon. One year later it hadn't been released, with no
date given as to when (or even if) it was going to be released. I
already had a board laid out and ended up having to redo the whole CPU
section. (Grrr!) That's when I looked into the ARM series.

ST Micro, Atmel, TI, Freescale, etc all make ARM variants, so it's easy
to change sources when different features are required (or a company
screws you over). Programming them is like programming a PC. No more
bank switching code (woo hoo!), and no more separate pointers for FLASH
and RAM.

The ZVG uses Atmel parts. Obviously a firmware update could turn the ZVG
into a real nice pattern generator, but if I were to redesign it, I
would definitely go ARM. They're just so damned easy to use, and with
that kind of power, throw in an emulator and you have a CCPU on chip!
It'd probably end up being cheaper as well, or at least very similarly
priced.

For your design, you could probably have run the vector generator almost
completely in the background, using the DMA controller and timers, and
in the foreground run an FFT on the ADC inputs and based your patterns
on frequency, beat, as well as amplitude. Same part count, similar cost.

-Zonn

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Received on Mon Nov 14 18:46:31 2011