Sound ISD25xx

Adding Sound

The ISD2560 is obsolete (or, at the very least, difficult to find).The pages here are just for reference in case someone has bought a last batch of them, or any of the others in the ISD25xx family.


The important thing to note with the ISD25xx series is that the 60 second record time is the best quality. There are 90 second and 120 second IC’s made, but the sound quality is substantially less.

The ISD25xx series of IC’s have several different access modes. The easiest mode to use is the sequential mode. This is the equivalent to a button press, advancing the track when the pin is pulsed. The tracks stop playing automatically. At the end of all tracks the IC will stop playing and then start again from the beginning.
The tracks are stored in memory. If the memory address of a track is known then it can be played on demand. The ISD will give a pulse when the track ends.
Example code – Sequential mode (used in Halloween bucket) PDF

Sequential mode

Here is a bare bones schematic to allow the audio to be saved or played from the ISD2560

recorder schematic
To see the schematic better, right click and choose View Image.

Flip the switch SW3 to put the circuit into play or record mode. Pressing the button SW1 quickly will start the recording (red light lit) or the playback (green light lit) . To use a micro-controller to control this, connect it to an appropriate interface or output and pulse it high and low mimicking the switch.

You can also play a track if you know the location address of where the sound was stored. After saving the sound, I accessed each sound location in turn and wrote down the addresses.

Direct address mode

This example code is very long and thus can be hard to follow.

Example code of address mode. As used in my Talkie toaster (PDF)