Posted on December 14, 2016 at 14:07Hi, thanks for the response.
I have been testing with a native serial port on a Dell Precision T7600 desktop PC. I have also observed the problem using a plug-in PCI serial port expander (PCIe to High Speed Serial Port).
As I mentioned I already have a workaround, but will try your suggestion later if I get some time. A couple points regarding your suggestion:
1) I have been running an application that uses software handshaking, which after closing will result in STM32FlashLoader Demo having the connection problem.
2) The source code for STM32FlashLoader Demo indicates they are attempting to turn off handshaking as they should. They apparently are not doing it correctly.
In main() (STMFlashLoader.cpp) they have:
bool control = false;
and later
STBL_SetFlowControl(control);
In STUARTBLLIB.cpp they have:
STUARTBLLIB_API BYTE STBL_SetFlowControl(bool val)
{
Cur_COM.FlowControl= val;
return SUCCESS;
}
In the function CRS232::open() (rs232.cpp) they have:
if ( FlowControl == true)
{
dcb.fDtrControl = DTR_CONTROL_ENABLE;
dcb.fRtsControl = RTS_CONTROL_ENABLE;
}
else
{
dcb.fDtrControl = DTR_CONTROL_DISABLE;
dcb.fRtsControl = RTS_CONTROL_DISABLE;
}
On applications I have written which have not experienced problems, I have disabled flow control with:
dcb.fOutX = FALSE; // No xon/xoff used
dcb.fInX = FALSE;
dcb.fDtrControl =
DTR_CONTROL_DISABLE
;
dcb.fRtsControl = RTS_CONTROL_DISABLE;
dcb.fOutxCtsFlow = FALSE;
dcb.fOutxDsrFlow = FALSE;
dcb.fTXContinueOnXoff = 0;
For more info google: windows dcb
In my opinion Windows should (but apparently doesn't) default to no handshaking. There should be no residual effects from the last program using the COM port.
