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[Matthew Porth]

     Hello All,
     
        Now where am I....
     
        Ahem... I had a quick peek at the HT8955A specs and although the chip 
     may do a lot of useful stuff but doesn't cut the mustard. I really want 
     44.1Khz 16bit sampling for this thing.
     
        Thinking about this a little more I realised that because I am after a 
     straight echo (albeit with variable time) I do not need to interpolate 
     digital values in the delays memory as only the length of the buffer in 
     samples is changing as opposed to the length of the buffer in time. e.g. 
     the time to play each sample out is the same as the time to read each 
     sample.
     
        This board would also leave me with the ability to generate very short 
     echos and delays (which I like for screwing about with drum machine snares 
     and stuff).
     
        I am thinking of a microprocessor based design but have very little 
     experience of interfacing to CPU's at an electrical level (only at a 
     logical level if you know what I mean). I would opt for CPU's simply 
     because I am a programmer and have spent most of my life up to my neck in C 
     and assembler therfore, for me, it is an advantage. It does also allow a 
     little more flexibility in the sound and effect generation properties of 
     such a circuit. Any pointers to this kind of stuff (digital design) are 
     VERY welcome...
     
        I do like the idea of a bucket brigade analogue delay with din syncing 
     that would work very nicely but I want maximum signal quality. Further with 
     a reasonble embedded CPU or DSP the "warm" effects of could be mimicked.
     
        BTW, check out atmel (www.atmel.com) they have some nice things.
     
     
        Matthew.
     
     >At 10:38 AM 18/07/97 +0100, Colin Fraser wrote:
     >>I plan to build a delay similar to this except it will sync to DIN Sync.
     >>No CPU should be required - all you need to do is replace the clock 
     >>generator in your delay with the oscillator output of a phase-lock loop
     >
     >do people have strong opinions on whether to use a uart or a pic for this 
     >kind of thing? at the prices I see for the uarts in the Penfold designs 
     >etc it might be cheaper to use a small micro though not as simple overall 
     >with the programming.....are there any cheap easy useful digital serial to 
     >parallel doodads that I have missed in the last 15 years?
     >Certainly I know many people who want a very cheap lfo locked to clock
     >
     >Using the sync pulses or even a click loop running concurrently with the 
     >main track it should be possible to make a frequency to voltage convertor 
     >to give a tempo-dependent control voltage. This could be used to drive a 
     >linear vco to drive a delay line clock for either a MN bucket brigade or 
     >perhaps even a HT8955 codec (with some hacking).......using a click would 
     >mean no need to decode the midi string....don't throw away any of those 
     >d*gital drum machines
     >
     >paul perry melb aust