Teensy 4.1 and DSP performance, and possible alternatives

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mah

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Hi, im trying to get my head around dsp and micro-controllers, from the all the documentation of the i.MX RT1060 i cant find anything about dsp features, but the stm32h7 talk about great dsp performance in the header on the product page, https://www.st.com/en/microcontrollers-microprocessors/stm32h743vi.html
And then there's things like i.MX RT600 with a dsp co-processor..

My project does not do any audio. but alot of signal processing with a adc, dac midi, etc, mostly routing/converting signals, generating envelopes, lfos, sequences, and such, "control signals". i think a sample rate around 5-10khz will suffice. should i stick with the teensy 4.1, or look at the stm32h7 series, or even go with a dedicated DSP chip?
What will give me the best performance?
 
You can generally expect Teensy 4.0 & 4.1 to give about 25% better DSP performance than STM32H7.

They have exactly the same Cortex-M7 processor, but Teensy's runs at 600 MHz compared to only 480 MHz on the STM32 part. All other factors being equal, 25% higher clock speed on the same CPU means 25% higher performance.

But not everything else is perfectly equal.

The other feature that makes a huge difference in performance is the tightly coupled memory. Teensy has 512K which can be assigned in 32K granularity between code & data. STM32H7 has only 192K, where the assignment is fixed to 64K code and 128K data. To be honest, this TCM size difference only matters if your speed critical code & data doesn't fit in the available memory, forcing you to put some of it in the other slower memory. And in that less-than-ideal scenario, the larger L1 cache size in Teensy 4.x will also help. If everything you need to do fits into 192K, the larger 512K TCM on Teensy 4.x only gives you room to do more someday. If you need more than 192K, definitely go with Teensy. TCM is essential for getting the full performance from Cortex-M7.

Usually the differences in peripherals don't have much impact on overall performance. Usually. For your application with a relatively low sample rate of 5-10 kHz, it's hard to imagine that will matter.

Whether you should go with a Cortex-M7 or a dedicated DSP is a much harder question to answer. It really depends on your application.

But if you're application is basically generating control signals for modular synth systems, any of these chips is probably plenty capable. To get an idea of the incredible amount of DSP capability, check out the recent thread about the Moog-like ladder filter...
 
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