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I was looking for cost effective voice playback IC and came up to ISD 1700 series. Another brief datasheet is here. I don't believe with the same footprint and only for 3-4 bucks I can get up to 16 min voice playback(if I am wrong correct me). However I wasn't able to find how to program the chip through digital channel.

If anyone has experience with this ICs - can I program the voice through SPI interface by storing voice samples directly into flash memory rather than recording from mic?

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The ISD chips I've worked with, and the 1700 looks like it's no exception, store audio in analog format. I think they write data by starting with every memory cell erased, and then program hit memory cell corresponding to each audio sample until its voltage matches that of the sampled audio input. The SPI bus serves to control which parts of the analog memory will be read and written, but does not have any means of reading or writing its content. If you want to program the devices, you'll have to design or buy a test fixture to feed in analog data.

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Do you happen to know any alternative low cost IC capable of programming samples digitally? Having fixtures is not option if your samples are language dependent and you would like to change language with new device firmware. –  Pablo Feb 26 '13 at 23:18
    
As @supercat has indicated, most of these chips are going to require you to feed in your analog audio via a programming jig of sorts. In fact, that's just what we do. We have a windows app we created which manipulates IO while playing back prerecorded messages. The way we work around the language issue is, we pre-program all languages we need to support (via our programming jig). We then "change" languages in firmware by simply playing back the same prompt in another language. –  Jason Feb 27 '13 at 3:16

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