Hello RIOT Team,
1 Question:
I try to calculate some floating point digits on the SAMR21-xpro Board.
When I print the floating point digit it shows me nothing.
My Code:
=================================================================
uint32_t time_diff = 554;
double distance = (33./2000.) * time_diff;
printf("distance = %f cm\n",distance);
=================================================================
Output:
=================================================
2019-07-31 14:36:58,631 - INFO # distance = cm
=================================================
Stack Overflow [1] tells me that floating point are disabled by default
on arm-gcc.
Whats the trick ??
What should I add to the Makefile ?
2. Question:
If I try to print (using printf) uint64_t variables I have the some
problem as above.
3. Question:
How precise is the current system time on RIOT ??
I set a GPIO HIGH and LOW with a time difference of 100 and less
microseconds. Before I set the GPIO HIGH and LOW, I call function [2].
If I compare the time with an oscilloscope I get horrible deviations.
What is the best way to measure microseconds and on RIOT with the
highest accuracy.
[1]
https://stackoverflow.com/questions/12703307/arm-none-eabi-gcc-printing-float-number-using-printf#25723994
[2] static uint32_t xtimer_now_usec()
--
Best Regards
Oliver Koepp
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