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by Pito
Sun Apr 23, 2017 6:04 pm
Forum: STM32F4 Boards
Topic: FPU on F407 - how to
Replies: 99
Views: 1040

Re: FPU on F407 - how to

FYI - I've replaced the code for printing the floats (we use it in the Integration Benchmark - fixed) as the code did an error with other calculation I've done recently. Instead of getting 100.0 I got only 10.0..
by Pito
Sun Apr 23, 2017 5:57 pm
Forum: General discussion
Topic: Problem with measuring very short pulses
Replies: 11
Views: 123

Re: Problem with measuring very short pulses

Does the ringing use a different pulse's Period?
Measuring periods only could be easier..
by Pito
Sun Apr 23, 2017 5:37 pm
Forum: General discussion
Topic: Dhrystone and Whetstone Benchmarks for STM32F103
Replies: 161
Views: 7409

Re: Dhrystone and Whetstone Benchmarks for STM32F103

Splitting the source file in three is ABSOLUTELY ESSENTIAL !!! I messed yesterday solving following issue: 1. in CMSIS DSP FFT example I generated 3 sinus tones with diff freqs and ampls 2. in a loop I sum up 3 sins to get the signal 3. while I worked with 1 file, it accepted only 1 (one) sinf in t...
by Pito
Sun Apr 23, 2017 4:32 pm
Forum: General discussion
Topic: Dhrystone and Whetstone Benchmarks for STM32F103
Replies: 161
Views: 7409

Re: Dhrystone and Whetstone Benchmarks for STM32F103

-Os, no -g, eabi-4.8.3-2014q1, -mfloat-abi=hard -mfpu=fpv4-sp-d16 -fsingle-precision-constant, 240MHz clock, Black 407ZET Loops: 1000Iterations: 10Duration: 6988 millisec. 1677248483 clocks C Converted Single Precision Whetstones: 143.10 MIPS Using the standard code. Indicate your eabi-arm version, ...
by Pito
Sun Apr 23, 2017 4:20 pm
Forum: General discussion
Topic: Dhrystone and Whetstone Benchmarks for STM32F103
Replies: 161
Views: 7409

Re: Dhrystone and Whetstone Benchmarks for STM32F103

-Os, no -g, eabi-4.8.3-2014q1, -mfloat-abi=hard -mfpu=fpv4-sp-d16 -fsingle-precision-constant, 168MHz clock
old repo, classic source in 1 file.

Code: Select all

Loops: 1000Iterations: 10Duration: 9984 millisec.   1677419955 clocks
C Converted Single Precision Whetstones: 100.16 MIPS
by Pito
Sun Apr 23, 2017 11:05 am
Forum: STM32F4 Boards
Topic: FPU on F407 - how to
Replies: 99
Views: 1040

Re: FPU on F407 - how to

"softfp" does not mean software floats.
It does mean the FPU uses the standard registers for parameters passing to the FPU. It is for compatibility reasons.
Both -hard and -softfp use the FPU.
It may happen the -softfp with FPU off will use software math routines, not verified yet.
by Pito
Sun Apr 23, 2017 10:56 am
Forum: STM32F4 Boards
Topic: Improving F4 core (libmaple based)
Replies: 121
Views: 1253

Re: Improving F4 core (libmaple based)

Can somebody check whether the Serial (not the SerialUSB) works above 115k2?
Tried with 460k and 920k speeds with no luck.
by Pito
Sun Apr 23, 2017 12:40 am
Forum: STM32F4 Boards
Topic: Improving F4 core (libmaple based)
Replies: 121
Views: 1253

Re: Improving F4 core (libmaple based)

FYI - serial over usb works fine at 240M with F407 here..
by Pito
Sat Apr 22, 2017 9:55 pm
Forum: STM32F4 Boards
Topic: FPU on F407 - how to
Replies: 99
Views: 1040

Re: FPU on F407 - how to

I've put the asm enable code before the __libc_init_array(); in start_c.c and it works. .. #if defined (__GNUC__) && defined (__VFP_FP__) #warning enabling harware fpu __asm volatile ( " ldr.w r0, =0xE000ED88 \n" /* The FPU enable bits are in the CPACR. */ " ldr r1, [r0] \n&qu...
by Pito
Sat Apr 22, 2017 6:02 pm
Forum: STM32F4 Boards
Topic: FPU on F407 - how to
Replies: 99
Views: 1040

Re: FPU on F407 - how to

And finally 3 tones, amplitudes 100000.0 at 50, 100.0 at 120 and 0.1 at 230. That means 60dB+60dB difference in amplitudes. Settings as above.
You may see the tone at 230 is still visible (luckily not hidden in the noise background) despite the large numerical noise of float.
FFT 3 tones.JPG
FFT 3 tones.JPG (63.11 KiB) Viewed 102 times

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