[sdiy] Crude sampler chip

[Tom Bugs]

I think CRUDE is just the right word.!.
That's not to say that the sounds don't have a clunky wonder charm, but...
...getting these chips to behave well while also making them stand on 
their heads can be tricky!
But the sound of slowing things right down can be really great.

I'm sure someone who can use micros well could get 'em running rings
(or you'd just build something like Harvestman is offering!)

The addressing:
Dave's point about there being 160 addresses is right -- you've got an 8 
bit address port, but when the two highest bits are set to 1 then the 
chip goes into 'mode select' and the other address pins change their 
function.

One potential area of problem which maybe rules out some ideas for 
delays etc is that you can only record about 100,000 times - thats 
plenty if you're just looping long segments, but if you're sampling many 
times a second then I'd guess the chip may die before too long?

Clocking -- as mentioned, I've used the 4046 PLL for a VC clock.
The problem here is that these don't have a really high max freq (only 
0.8MHz at 5v supply - from datasheet) and this seems to give problems 
for using the loop mode.
Any other ideas for a faster VC clock?

All best,
Tom


Dave Magnuson wrote:
> ---- Original Message ----- From: "Derek Holzer" <derek at umatic.nl>
> To: "Dump Static" <xpandrew at ph.k12.in.us>
> Cc: <synth-diy at dropmix.xs4all.nl>
> Sent: Wednesday, October 10, 2007 4:05 PM
> Subject: Re: [sdiy] Crude sampler chip
>
> <SNIP>
>
>
>> But a more brave soul could look into the digital addressing 
>> functions of the chip for cheap, noisy granular synthesis. > -- 
>
> <SNIP>
>
> I have the app notes / design guide for the ISD1xxx family.   
> According to the book, addressing is quite simple:
>
> You can use 8 bit binary address values from 0-159.    Divide the 
> total storage time by 160, and this is the length of each step in the 
> address.
>
> With ISD1020A as an example (20 sec) = 125 mSec per step.  Using 
> decimal equiv of each address:
>
> address of 0 = 0 sec
> address of 1 = .125 s
> address of 8 = 1.00 sec
> etc.
>
> Seems pretty simple, although I've never tried it.   It says you can 
> start playback or recording at any of these points.  The book also 
> mentions cascading, looping, etc.  Pretty neat if you can find a copy
>
> Dave Magnuson
>
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