RS232 Hardware Flow Control in Windows 7
Posted: Fri Oct 02, 2015 2:55 am
I am using my Fit-PC3's serial port to control a device which uses hardware flow control. I'm also using the Python serial library to do so.
When I boot into Linux, the flow control works as expected.
When I boot into Windows 7 the same code does not work.
I have found I get an appropriate response from my device if I unplug and reconnect it, but only one response until I unplug/re-plug again.
I the Device Manager I have set the serial port to use Hardware Flow Control.
Is there some setting that is stopping RTS/CTS from working in Windows 7?
Regards,
John
Further to this I have done some testing on various PCs.
I dug out my old RS-232 Level Tester and found the following quiescent states:
HP Desktop PC - Windows 7: TX, RTS, DTR all Inactive (-ve)
Fit-PC2 - Windows 7: TX, RTS, DTR all Inactive (-ve)
Fit-PC2 - Linux : TX, RTS, DTR all Inactive (-ve)
Fitlet - Linux : TX, RTS, DTR all Inactive (-ve)
Fit-PC3 - Linux : TX, RTS, DTR all Inactive (-ve)
Fit-PC3 - Windows 7: TX, RTS, DTR all Asserted (+ve)
So far my research turns up that all lines (TX, RTS & DTR) should be Inactive (-ve) in the quiescent state (before and after transmissions).
The last one is odd: Fit-PC3 with Windows7.
I'm tending to think that there is a driver issue or setting that is causing the incorrect levels.
There doesn't appear to be any driver updates for the serial port on the Fit-PC website.
So can anyone tell me what setting I need to make or driver to update to fix this?
Thanks,
John
When I boot into Linux, the flow control works as expected.
When I boot into Windows 7 the same code does not work.
I have found I get an appropriate response from my device if I unplug and reconnect it, but only one response until I unplug/re-plug again.
I the Device Manager I have set the serial port to use Hardware Flow Control.
Is there some setting that is stopping RTS/CTS from working in Windows 7?
Regards,
John
Further to this I have done some testing on various PCs.
I dug out my old RS-232 Level Tester and found the following quiescent states:
HP Desktop PC - Windows 7: TX, RTS, DTR all Inactive (-ve)
Fit-PC2 - Windows 7: TX, RTS, DTR all Inactive (-ve)
Fit-PC2 - Linux : TX, RTS, DTR all Inactive (-ve)
Fitlet - Linux : TX, RTS, DTR all Inactive (-ve)
Fit-PC3 - Linux : TX, RTS, DTR all Inactive (-ve)
Fit-PC3 - Windows 7: TX, RTS, DTR all Asserted (+ve)
So far my research turns up that all lines (TX, RTS & DTR) should be Inactive (-ve) in the quiescent state (before and after transmissions).
The last one is odd: Fit-PC3 with Windows7.
I'm tending to think that there is a driver issue or setting that is causing the incorrect levels.
There doesn't appear to be any driver updates for the serial port on the Fit-PC website.
So can anyone tell me what setting I need to make or driver to update to fix this?
Thanks,
John