Q: How to implement real-time signal processing on STM32 using DSP instructions?
Answer
STM32F4/F7/H7 contain a Cortex-M4F/M7 DSP instruction set (SIMD MAC) and optional FPU. Enable CMSIS DSP library for FFT FIR matrix operations. Use arm_cfft_f32() for FFT with 256-1024-point transforms in less than 1 ms at 180 MHz. For audio processing implement a biquad (IIR) filter chain using arm_biquad_cascade_df1_f32(). The FPU significantly accelerates floating-point math – always use -float-abi=hard and -mfpu=fpv4-sp-d16. For deterministic DSP (motor control) use CMSIS-DSP with fixed-point (Q15/Q31) to avoid FPU initialization latency on exception. Consider STM32H7s MDP (Macrocell Data Processing) for hardware-accelerated convolution.
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