We are a design house and have much experience in this field?

Can we be of assistance?

Richard Sloan

 >>  I am mostly a software guy, and I've done a lot of reading about PICs
 >>  but am just now getting my hands dirty.

 >>  I may end up using ISD's but I keep thinking there must be a better
 >>  way.  I need to build about 100 identical circuit boards, so every $
 >>  will add up.

 >>  I've thought about using a dedicated PIC which would just read sound
 >>  data from memory and send it out via PCM or a D2A chip...but most of
 >>  the memory chips for use with a PIC seem quite small.

 >>  One think I don't like the ISD's is the busy work it will take to
 >>  program 100  of them.  Storing sound data in 100 flash memory chips
 >>  seems a bit more elegant.

 >>  But how much memory can you really interface to a PIC?  And how much
 >>  will it cost?

 >>  Maybe the ISD turns out to be the crude but effective solution to the
 >>  problem?

 >>  Phil


 >>  >  > What DSP are you using and what is the part price?
 >>  >
 >>  >Both are now obsolete, and the price when they were alive was
 >>  >around NZ$7. I considered getting in touch with Rochester (???), a
 >>  >US company that takes the original manufacturer's masks and
 >>  >makes new chips for you, but the time I think would be better
 >>  >spent on developing a s/w alternative on a fast micro like PIC
 >>  >or AVR. As the original parts were designed for DRAM (in those
 >>  >days when power consuption was not the issue it is now and
 >>  >micros were a glint in an engineer's eye) an obvious enhancement
 >>  >is to design for the modern micro-power mega-SRAMs. Although
 >>  >the circuit I use currently is a DSP/PIC hybrid and works very well, it
 >>  >would be fairly easy to dispense with the DSP in a new design.
 >>  >Having PCBs and DSPs to hand makes that unnecessary right now
 >>  >
 >>  >>  Did you have to
 >>  >>  write the DSP code, or is this a hardwired function of the chip?  Do
 >>  >>  you know of any contemporary chips that might be similar?
 >>  >
 >>  >There is no coding, apart from a a couple of lines to send commands.
 >>  >The DSP handles the rest. I would luuurve to find a replacement but
 >>  >AFAICT there is nothing available in a single chip. Everything I've
 >>  >looked at so far is at the "scruffy" end of the market (eg ISD) and is
 >>  >good only for speech frequency bandwidth. For anything else the
 >>  >sound is so treble-less I can't use them
 >>  >
 >>  >--
 >>  >http://www.piclist.com#nomail Going offline? Don't AutoReply us!
 >>  >email listserv@mitvma.mit.edu with SET PICList DIGEST in the body

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The Mind Factory INC               =20
Richard Sloan                      =20
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rsloan@themindfactory.com

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