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Topic: ISD1700 Series SPI Command Control (Read 568 times) previous topic - next topic

bigmike333

Hello Friends. I have a question about the ISD1700 series of voice record / playback chips, under SPI control. I have obtained a demo board of the ISD1730 from Nuvotron and am driving it with an Arduino Uno. I am able to make this board do all the basic functions, such as play, stop, reset, power-up, volume up or down, etc. I have no issues talking with the chip, except for one...

First of all, in regular pushbutton mode, I can record a message using the on-board microphone. I can play it back with no problem. I can play it back through SPI comands, adjusting the volume as needed, via SPI. I know how to talk to the APC registers OK. Board works great, sounds pretty good.

The problem is, when I configure the analog path (APC) with SPI to use the internal microphone, I get nowhere. It is recording, but it is evidently listening to the ANA-IN pin, not the microphone. Tried every way I possibly could, just in case there was a typo on the datasheet. It simply will not pass audio from the microphone in SPI mode. It only records silence from the ANA IN.

Can someone please prove me wrong on this? Please respond if you have successfully done it. Again, I can talk to the chip fine, I just need to know if ANYONE has ever got it to work, despite the data sheet saying it should. That's all I really need, in case I'm just wasting my time. The designer guide shows a suggested schematic for using it in SPI mode, and they do not show a microphone connected.

Thanks.

bigmike333

OK, well I have finally found a fix for this, with much researching on the web. In a nutshell, the demo board available from the factory has a problem on the PCB. I found this information here:

http://users.rcn.com/ted.johnson/isd.htm

Kudos to this gentleman who discovered the fix. This really pertains to the factory demo board, only. I ordered another type of ISD1760 record/playback module from Amazon. I was able to control it perfectly, via SPI, and pass the microphone audio. This required no modification.

I guess this is a common scenario, but it is frustrating when factory supplied demo boards have errors in their design. I can't begin to imagine the countless man-hours wasted, thinking something is wrong with the code.

Here is a link to the device I purchased from Amazon that works well:

https://www.amazon.com/gp/product/B0181RP5Z8/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

This is not an advertisement for them, only a report of a product that may save you lots of development time.

Cheers!

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