What is the MaixPy FFT (K210) input format?

[JeffreyUrban]

On the page: sipeed_wiki/docs/soft/maixpy/en/api_reference/Maix/fft.md

The documentation for the K210 Maix.FFT function does not clarify the input format(s) for the FFT function.

Including:

• Bit width(s) of values
• Signed and/or unsigned values
• Little-endian or big-endian values
• Real and/or complex values

I'm continuing to look at the other available documentation and code for the K210, but have not yet found clarification there.

[JeffreyUrban]

Looking for relevant information from the K210 documentation...

The K210 datasheet specifies:

3.10 FFT Accelerator The FFT accelerator is a hardware implementation of the Fast Fourier Transform (FFT).

• 64-point, 128-point, 256-point or 512-point length
• FFT and IFFT operation modes
• 32-bit or 64-bit input data width
• Supports pure-real, pure-imaginary or complex input data
• DMA transfer support

The K210 Standalone SDK Programming Guide (pp 102-106) describes the details of the C API, with an example and input data struct definition.

[JeffreyUrban]

I didn't find any mention of the system data endianness in the K210 documentation.

Searches suggest that RISC-V typically uses a little-endian data order.