How to control the uart

Question

Here is my general idea.I generate a matrix in Matlab. I want to transmit the numbers in matrix into FPGA. And these numbers will be sent to an algorithm implemented FPGA board. The algorithm will deal with these numbers and new result is sent back to PC(Matlab, I want to compare the result from MATLAB).

I know transmitting these numbers to FPGA board. I need a UART. I have one. I also have done the algorithms in FPGA. But I don't know how to transmit the numbers from Matlab to FPGA. Exactly to say, I don't know how to control uart. How does uart know the data come in? Shall i add like "FF" file head to transmitting number? ...I am totally lost now. I have no idea how to connect Matlab to FPGA. Please give me some suggestions. Thanks.

radarman · Accepted Answer

Do a google search on "Matlab serial I/O". I came up with this rather promising link in under 30 seconds.

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You will need some sort of control logic in the FPGA to handle the UART, but if you are already implementing algo's in both MATLAB and VHDL/Verilog, a simple state machine should be no problem.

Duane Clark · Answer

Every byte of data sent via the UART starts with a start bit and ends with a stop bit (in the most commonly used scheme, 1 start bit, 1 stop bit, no parity). In between transmission of data, the UART holds the stop bit level. UART receivers therefore know that no data is being sent until it receives a start bit, and it knows that the next 8 bits are data.

All this is handled by the hardware and is largely transparent to you. Within the FPGA, the UART receiver will provide a bit indicating that data has been received.

ZHI · Answer

Thanks radarman and Duane Clark. I have read that link. It is quiteuseful.I want to make a simple test for transmission data between PC(matlab)to FPGA(UART).  I can generate the  file and download into FPGAboard successfully.Can I ask a question of user constraint file ? I have successfullydownloaded a LED flash into FPGA board before. I copied this exercisefrom the CD enclosed with the FPGA board. I remember before I implementit into FPGA board. I not only generate the .bit file also copied theLED user constraint file in the CD. Actually I am not quite sure thecontent of the constraint file. I just copied it. Now I want toimplement UART into FPGA board. I think it also needs one userconstraint file for implementing. I think the user constraint file isgenerated automatically when the programming file is generated. Butwhen I open the .ucf file, it is blank. What is the problem? Shall iwrite it by myself? I don't know how to connect the pin? Can youexplain the .ucf function for me...

ZHI · Answer

It is solved. Thanks all again.

How to control the uart

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