Hello everybody,
I am using the NUCLEO-L476RG to send simple ACII text over UART (RS232 adapter) or USB CDC as a virtual COM port. UART communication is working seamlessly but when I use the USB CDC library functions from STM there is hapenning something strange I cannot explain:
I am sending in regular intervalls ASCII-tesxt in the follwoing format: ABP;***;***;***\n
The * stands for different numbers. normally I would see this kind of text flow on a terminal like hterm:
ABP;***;***;***\n
ABP;***;***;***\n
ABP;***;***;***\n
... and so on
but with the USB CDC usage I see occasionally this:
ABP;***;***;***\n
ABP;ABP;***;***;***\n
ABP;***;***;***\n
ABP;***;***;***\n
ABP;ABP;***;***;***\n
when I halt the debugger to check if my character array is corrupted, it isn't. So my assumption is that there is something not working correctly with the USB CDC device library from STM. This is the code, that gets invoked when I transmit the ASCII-text:
sprintf(Communication.measure,"ABP;%ld;%ld;%ld\n",Patient.Systolic, Patient.Diastolic, Patient.MAP);
if(System.Mode == UART)
{
LPUART_transmit_message(Communication.measure);
}
else if(System.Mode == USB)
{
CDC_Transmit_FS(Communication.measure, strlen(Communication.measure));
}
as you can see, i am using the same array preparations for the USB CDC version as for the UART version, except that the UART version functions seamlessly. The big difference between both versions is that I only utilize USB CDC device library functions provided by STM, not my own.
Has anybody experienced something similar? Or has a good hint where to find the problem?
best regards
Benjamin
