1.8.2.8 mchp_rfft_fast_init_f32()

mchp_status mchp_rfft_fast_init_f32 (mchp_rfft_fast_instance_f32 * S, uint16_t fftLen)

Initialize a single-precision floating-point real FFT instance.

Parameters:
in,out S

RFFT instance structure

in fftLen

Length of the real input sequence

Returns:

  • MCHP_MATH_SUCCESS Initialization successful

  • MCHP_MATH_ARGUMENT_ERROR Unsupported FFT length

Note:

Supported FFT lengths: 32, 64, 128, 256, 512, 1024, 2048, 4096

Only the twiddle data for the selected FFT length is compiled in.

When FFT sizes are known at build time, it is recommended to enable only the required USE_FFT_LEN_xxx macro so the compiler pulls in the correct twiddle-factor table and eliminates unused data.