Arduino for STM32

I've been using the same compiler as the official STM core (with the 239Mflops @168Mhz). There is only 1 FPU inside. Again, you cannot get more than 119 Mflops at 84MHz. You have to enable the printing out the results as I have done !! Otherwise the compiler may optimize out the entire blocks of the...

@ag123: I do not understand how can you get similar results @84MHz as I get @168MHz (-O3, FPU on) Me: Loops: 10000 Iterations: 1 Duration: 4171 millisec. 0 clocks C Converted Single Precision Whetstones: 239.75 Mflops You: Loops:10000, Iterations:1, Duration:4654.92 millisec C Converted Single Preci...

8pin SPI FRAM would be a better option there, imo.

PB11 is not available on the board, it seems.

PF 2020!

ag123 wrote: ↑Tue Dec 31, 2019 4:00 pm it works STM32F401 black pill - steve's libmaple core

Looks nice..
Quality?
Fake stm32F401 chip?
Does it fit into the solderless breadboard fine?

As above with -O3 and with your setting: 10000 loops, iterations 1 Loops: 10000 Iterations: 1 Duration: 4171 millisec. 0 clocks C Converted Single Precision Whetstones: 239.75 mflops 0 0 0 1.00 -1.00 -1.00 -1.00 0 120000 140000 120000 -0.00 0.00 -0.00 0.00 120000 140000 120000 120000 -0.00 0.00 0.00...

The max speed of Bpill's SPI1 is 36MHz clock. For a single byte you need "best case" 36/8=4.5MB/sec.
There is an overhead of course, thus the speed will be lower.

The F407 uses SDIO with SDcard for higher speeds.

64b or 32 fpu is basically the "same" speed. 64b vs. 32b in sw - 64b is ~2x slower and the lib code is ~2x larger. PS: added the whetstone built with Roger's core but with the xpack-arm-none-eabi-gcc-9.2.1-1.1, F407ZET @168MHz, FPU on, default Loops: 1000 Iterations: 10 Duration: 8396 mill...

Well, the double precision would be something more interesting to have handy.
Single p. is rather limited in use, imho.