I have a PCBA with an ADAU1401 performing some ADC-DSP-DAC tasks and it works pretty fine. now I need to add a big delay to the audio, so I came to the possible solution of codec+DSP.
I am trying to set up a big delay (up to 34 seconds) to a pair of audio outputs. I have thought of the ADAU1452 (ADAU145x and ADAU146x series) to perform this task, due to the External SPI Delay feature. My audio signal has a data rate of 48 kSa/s. I have done some calculations and I would need 24.4 Mib (3.05MiB) of memory per channel for this purpose. Up to here, it seems fine, it would be a couple of 4MB memories (or a single memory of 8MB, if this is possible).
Now, the tricky part: I just find NOR flash memories in this range of memories and simple SPI interface. I am concerned of the duration of the memory, as it will be cycling all the memory around twice a minute (in the best case, which would be the DSP writting to the memory in full pages). This gives us (for a "Min. 100K Program-Erase cycles per sector" memory) around 50k minutes of working time, which is around 34 days of continuous delayed audio played. I am planning to use these equipments in installations that should be installed for years and years.
So, my question here is: is there any other kind of memories (that I am not aware of) or any other way around that can make this project to trully work?
Many thanks in advance.