Description
Description
- Type: Bug
- Related issue: equeue_mbed problem with sleep mbed-events#16
- Priority: Major
Bug
Target
STM32F4
Toolchain:
GCC_ARM
mbed version:
Revision 131 (bundled with platformio)
Expected behavior
Using Timeout to creating a callback to turn off a pin after 50us, I expect to see the pin turn off when looking with an oscilloscope. I am create an EventQueue from mbed-events, which is not expected to interact with the Timeout.
Actual behavior
On NUCLEO L053R8: The callback turns off the pin after 78us
On NUCLEO F401RE , the pin goes high, and stays high. Debugging with GDB indicates that the callback never gets called. (same behaviour on Discovery F4 after changing my_pin to a valid pin for this board)
Replacing the call to queue.dispatch() with while (1) {} means that the callback is now called properly on both targets. This suggests that some code called by the queue is blocking interrupts.
The issue has some similarities to ARMmbed/mbed-events#16, where the sleep() function in the HAL is a suspect. Since the behaviour depends on the target, I have raised the issue here, where all target dependent code lives
Steps to reproduce
The following example code illustrates the problem:
#include "mbed.h"
#include "mbed_events.h"
DigitalOut my_pin(D2);
void pin_off(void)
{
my_pin = 0;
}
EventQueue queue;
int main(void)
{
printf("starting\n");
Timeout to;
while (1)
{
my_pin = 1;
to.attach_us(pin_off, 50);
//while(1) {};
queue.dispatch();
}
}