How many possible instructions ADAU1445/1446

The ADAU144x's core clock runs at about 172 MHz, which allows 3584 (3.5k) instructions/frame to be executed at fs=48kHz. The program RAM size is actually 4k words, but only 3.5k of these instructions can be run per frame. For most designs, all instructions will be executed in each frame, so you should limit your instructions to 3584. A future version of SigmaStudio should be fixed to show max instructions of 4k, and maximum MIPS of 3.5k.

Cool. I'm doing some feasibility studies of different processing configurations and noticed that while the number instructions used changes as expected based on how I have the schematic set up the number of available instructions does not change when I change the sample rate on the AsrcIn block where all my processing starts. I take it that once this issue is addressed the number of instructions available would be listed as 3584, 1792, or 896 in the compiler's output for sample rates of 48, 96, or 192kHz, respectively. Is that correct? (I've verified the link output shows sample changes on the ASRC block propagating through to the outputs.)

SigmaStudio's compiler output report does not change the number of total instructions it shows based on the sample rate. If you are designing a system at a higher fs, such as 96 kHz, then you should just be sure to limit your total instructions to 1/2 of what you can use at 48 kHz. For the ADAU144x, this is a limit of 1792 total instructions.

When you're changing the sample rate of your design, make sure that you're following the procedures outlined in this FAQ. This will ensure that all of your processing and filter calculations are done at the correct sample rate.