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Serial over USB - printf() on F407
Posted: Sat Jan 25, 2020 7:56 pm
by Pito
Hi STM Core experts,
I've been trying to start with the STM core..
Build the Whetstone benchmark, with SerialUSB.begin(115200); and using printf(..).
The Arduino 1.8.11 IDE and 1.8.0 STM core installed today.
I do program the BlackF407 via J-link, SWD, it flashes ok (from 0x8000000).
My serial setting is - see below. Not sure how to setup it..
I cannot get a single output from the serial, it connects to TeraTerm as COM20 (STM CDC driver, works with BluePill fine) but nothing happens.
.
- F407 setting.PNG (67.72 KiB) Viewed 10793 times
Re: Serial over USB on F407
Posted: Sat Jan 25, 2020 8:01 pm
by BennehBoy
Have you tried just print? I think there's a recent pr which allows printf to work on the CDC serial, but unless you use the repo version then it's not available. Unless my memory is failing me (again!)
See here ->
https://github.com/stm32duino/Arduino_C ... 2/pull/867
Re: Serial over USB on F407
Posted: Sat Jan 25, 2020 8:05 pm
by Pito
Code: Select all
void setup() {
delay(3000);
SerialUSB.begin(115200);
SerialUSB.println("Hello Whetstone benchmark!!");
int count = 10, calibrate = 1;
long xtra = 1;
int section;
this works..
Re: Serial over USB - printf() on F407
Posted: Sat Jan 25, 2020 8:20 pm
by Pito
I've patched manually the Print.cpp lines 199-220, restarted arduino ide, built, flashed, and it works..
Code: Select all
##########################################
Single Precision C Whetstone Benchmark
Calibrate
0.14 Seconds 1 Passes (x 100)
0.71 Seconds 5 Passes (x 100)
3.53 Seconds 25 Passes (x 100)
Use 70 passes (x 100)
Single Precision C/C++ Whetstone Benchmark
Loop content Result MFLOPS MOPS Seconds
N1 floating point -1.12475013732910156 79.059 0.017
N2 floating point -1.12274742126464844 57.366 0.164
N3 if then else 1.00000000000000000 84.244 0.086
N4 fixed point 12.00000000000000000 250.569 0.088
N5 sin,cos etc. 0.49909299612045288 1.318 4.420
N6 floating point 0.99999982118606567 15.746 2.398
N7 assignments 3.00000000000000000 13.617 0.950
N8 exp,sqrt etc. 0.75110614299774170 1.489 1.749
MWIPS 70.908 9.872
Re: Serial over USB - printf() on F407
Posted: Sun Jan 26, 2020 9:03 am
by BennehBoy
Re: Serial over USB - printf() on F407
Posted: Sun Jan 26, 2020 9:47 am
by Pito
Not sure what was actually wrong.. Might be I messed up something, first time with STM core and not using Arduino IDE for ages..
Re: Serial over USB - printf() on F407
Posted: Sun Jan 26, 2020 10:08 am
by fpiSTM
that is normal.
printf() on 1.8 print only on an U(S)ART.
Originally, it was used only for debug purpose.
It has been extended to be able to use printf with the class Print but I didn't manage to use it with SerialUSB.
So, it was fixed here:
https://github.com/stm32duino/Arduino_C ... e10280278f
It is available in the master and will be available in the next release thanks the boards manager..
Re: Serial over USB - printf() on F407
Posted: Sun Jan 26, 2020 11:04 am
by Pito
Thanks!
We have got plethora of flash in F4xx, no problem with printf!!
