C5505 DSP Interface With Matlab/Simulink

hi, i am doing project of doing ECG on C5505 EVM. As till now i have successfully connected the EVM to pc and getting the signals. Now 1)i wanted to know how i be able to interface it with Matlab/Simulink. i can use both the USB or RS232 port.

2)I want the plots of ECG in realtime so that i can view and further analyze them

3)One thing more is it true that Simulink can be much easier for interfacing the DSP?? Cause i am new to matlab and dont know the code. It would be great help... Thanks...

Answer 1

[Kaustubha Govind]

1. You can interface with a serial port using a serial port object. Not sure about using the USB interface - does the EVM manufacturer provide driver DLLs? If yes, you can load it into MATLAB using either loadlibrary or calling it from a MEX-function.
2. No inputs from me here - were you looking for advice on real-time processing? Note that since MATLAB/Simulink is not running on a real-time OS, it cannot deal with high-frequency inputs, but you may be able to get this working if MATLAB can acquire data fast enough for your application.
3. I wouldn't say that Simulink is necessarily easier for interfacing with a DSP, unless you want to generate embedded code from your model and download it to the target.

[Talha]

Thanks Kaustubha, for replying...

Now again answers for the previous questions...

1)No, no drivers given, so i'll choose Serial port obj...

2)yes i was asking about Real time... so can't matlab plot graph during the dsp transmitting ecg data...i know it would take time for processing but a delay or so would not hurt much.

3)No codes generating problem, all i have to do is make the ecg plots and do some analyzing on them

So is there is a way i can only use simulink and no requirement of plain Matlab required???

[Kaustubha Govind]

I think you might be able to use the Instrument Control Toolbox with Simulink to achieve this (http://www.mathworks.com/help/toolbox/instrument/brbv41k-1.html), but if you would prefer staying with base MATLAB, then you will need to implement simple MATLAB functions to send/receive data via serial port object and call those from Simulink using either the MATLAB Fcn block or a MATLAB S-Function block.

[Talha]

hi Kaustubha,

i have successfully connected the DSP with the Simulink through the Instrument Control Toolbox. Now new problem rose. i used the time scope to view the signals... but the problem is that it shows all the signals from different leads together which is of no use. Now how can i separate them individually??? What components could be used???

[Kaustubha Govind]

You can use the Demux block to separate the signal: http://www.mathworks.com/help/toolbox/simulink/slref/demux.html

[Talha]

hi Kaustubha,

i did what you said. i dont't understand how will i know which leads are coming into which scope(Sink). Cause i need to recognize the leads in order to measure Heartbeat etc...

[Kaustubha Govind]

You should probably check the EVM documentation to check what order the signals are written to the port in?

[Talha]

can i use Real time windows target for my configuration???

[Kaustubha Govind]

Real-Time Windows Target produces an executable that runs on a Windows-based kernel - it does not apply to EVMs. Why did you consider this product at all?

[Talha]

ook my bad...i have seen the documentations of the different packets coming in from serial port. Also they have told me to write my own S function in order to separate the leads data. One thing more what could be the reason for the high amplitude of order of 10x4...in the scope??

[Walter Roberson]

Is the maximum amplitude about 3 x 10^4? If so that would correspond to a signed 16 bit integer, which would be a fairly common sampling format (though unsigned 16 bit integer would probably be more common.)