Nuvoton ISD1700 series Voice recording/Playback IC.

[Chapman]

I am using a ISD1760PY (supplied in a Velleman-kit) which, when built up on their supplied PCB, works absolutely fine when driving a loudspeaker.

I now need to reconfigure the device to produce (unbalanced) audio (instead of via a loudspeaker) but have been unable to discover from the Datasheet and the Design Guide exactly how (in Standalone mode) the device should be rewired to do this.

Can anyone help please?

TIA - Dave.

 

[JimB]

A quick look at the datasheet and the design guide shows that pin 17 (AUD/AUX) can be used as a single ended output.

This pin can either be configured as a current output (AUD), or a voltage output (AUX).

The selection AUD/AUX is done in the APC register (Analog Path Configuration) can be done via the SPI interface.
My understanding after a quick read of the documents, is that the ISD1760 defaults to AUD mode on pin 17 if you want to use it in standalone mode without a microprocessor to write to the SPI port.
Look at example 1 on page 16 of the datasheet for a basic idea how to use this.

JimB

 

[Chapman]

Hi Jim B, thank you for those comments.

I also have the 'ISD-COB17xxx User's Manual' which relates to a COB/Demo board for the ISD1700 series which says :-

"Default setting is speaker output. If AUD is needed, remove the connection from centre pad to Sp- (Sp+) pad of J4 (J5) and reconnect the centre pad to Vcc (AUD) of J4 (J5) as shown (in a diagram of pads J4 and J5) below".

J4 Vcc Pin 13 SP+

J5 AUD Pin 15 SP-

It then says "Also need to install a jumper at J8 (AUD1-AUX) for AUD output".

Pin 17, when viewed on a 'scope and terminated in a 390 ohm resistor and a 100nF capacitor in parallel, does produce clean audio which I can use, but I assumed from the rather confusing information given in the ISD Demo board notes that it was also necessary to swap some wiring around to meet ISD's required configuration and achieve a proper (near line-level) audio output.

Rather than spend more time delving further into the pin-strapping puzzle I'll stick with the Pin 17 terminated and filtered audio which does exactly what I need.

Many thanks - Dave.