Real-time Workshop for serial communication: clear input buffer needed
in [Matlab]
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From: Jose on 9 Aug 2010 05:22 Hi guys, Is there anybody that could help on this? Thanks! "Jose " <jose.araujo(a)fe.up.pt> wrote in message <i3j1qd$6md$1(a)fred.mathworks.com>... > Dear all, > > I am having a problem using the packet input function on real-time. I am able to read the 17 bytes of data I am sending through the serial port in a good way BUT sometimes I end up having an extra byte in the frame which is making my buffer shifting one position every time this happens. > > E.g. > > byte 1 ... byte 17 = 17 bytes > byte 1 ... Garbage = 17 bytes > byte 17 (old) byte 1 ... byte 16 = 17 bytes > > So basically after some time I start only seeing the last bytes in the next frame, which is really bad. What I can do to fix this, in MATLAB code (http://www.mathworks.com/support/solutions/en/data/1-30N8YX/index.html?product=ML&solution=1-30N8YX) and in Labview is to Flush and Discard the Buffer (Purgecomm function in C). The thing is that I needed to use real-time simulink for this but Packet output doesnt do this automatically. > > Do you have any suggestions on how to do this? > > We have tried to do a C function S function to read the serial port in real-time, but first we used the windows.h to do this and it doesnt work as it is explained in the matlab help, and after that we built a C function based on the conio.h function which also doesnt work since it is made for pure RS232 serial communications (PORT1 to PORT4) and we are using USB (PORT5 to PORT9). > > Thank you! > Jose
From: Steven_Lord on 9 Aug 2010 09:33 "Jose " <jose.araujo(a)fe.up.pt> wrote in message news:i3ohbs$7em$1(a)fred.mathworks.com... > Hi guys, > > Is there anybody that could help on this? *snip* Determining what is causing this problem would probably require a lot more information about what exactly your code and/or model is doing than you've specified, so I recommend you contact Technical Support for help with this issue. -- Steve Lord slord(a)mathworks.com comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ To contact Technical Support use the Contact Us link on http://www.mathworks.com
From: Jose on 9 Aug 2010 10:47 Thank you Steve. Will do that. I basically just needed to be able to call the buffer clear function somehow in real-time. Jose "Steven_Lord" <slord(a)mathworks.com> wrote in message <i3p02d$9ds$1(a)fred.mathworks.com>... > > > "Jose " <jose.araujo(a)fe.up.pt> wrote in message > news:i3ohbs$7em$1(a)fred.mathworks.com... > > Hi guys, > > > > Is there anybody that could help on this? > > *snip* > > Determining what is causing this problem would probably require a lot more > information about what exactly your code and/or model is doing than you've > specified, so I recommend you contact Technical Support for help with this > issue. > > -- > Steve Lord > slord(a)mathworks.com > comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ > To contact Technical Support use the Contact Us link on > http://www.mathworks.com
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