[sdiy] Reverse Sawtooth

[Matthew Smith]

Quoth Paul Maddox at 25/01/11 08:52...
...
> There's a million and one ways to crack this nut, the trick is to try
> something and see what works for you!

Once I've done an "all on one chip" proof-of-concept, showing that I 
*can* get a waveform out of this rig, I still plan to have the final 
nut-cracking solution of a microcontroller being the timing source ONLY 
- synchronous counter and [E2|E]PROM. For $6 I can buy a 32k x 8 bit 
150ns EEPROM and that 32k isn't going to be shared with anything.

As much as anything, I'm looking for a cheap solution as I'm keen to 
divide my incoming signal and feed it into a set of modules so I'm 
timing at f, f/2, f/4, f/8.  (The division might not occur - I might 
just double the sample size for the lower octaves.)  Each module is then 
fed into a mixer before being given an envelope (if I actually use one,) 
filtering, etcetera.  In case you hadn't guessed, I rather like organs ;-)

But one step at a time - interrupt-triggered lookup then feed to DAC on 
an ATTINY2313 will be Experiment #1.  Seeing as how I've written the (C) 
code and have even started on the board in Eagle.

Now to head out to AusPost and see if Chamberlain has turned up!

Cheers

M

PS - an alternative to assembly is to use the inefficient coder's 
paradigm: throw more hardware at it (use a faster device.) See that in 
my business ALL the time ;-)

-- 
Matthew Smith
Smiffytech - Technology Consulting & Web Application Development
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