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1087 Discussions

RS232 IP Core on Ubuntu -- DE2-115

Honored Contributor II


I am using the RS232 IP core to send info from a DE2 board to a computer running Ubuntu. When run on Windows, the controller works fine, but when run on Ubuntu the something interesting happens and I cannot find any help with this issue. Here is what I have. 


A sample project (not the actual project I'm using, but something I made to debug the issue, the same thing happens in each):  

module serial( input CLOCK_50, output UART_TXD, input KEY ); reg data; reg valid; wire reset; assign reset = ~KEY; uart u0 ( .to_uart_data (data), // .to_uart_valid (valid), // .valid .clk (CLOCK_50), // clk.clk .UART_TXD (UART_TXD), // .TXD .reset (reset) // reset.reset ); reg preKEY1; always @(posedge CLOCK_50) begin if(reset) begin data <= 8'd5; valid <= 1'b0; preKEY1 <= KEY; end else if(KEY != preKEY1)begin data <= data + 8'd1; preKEY1 <= KEY; valid <= 1'b1; end else begin data <= data; valid <= 1'b0; preKEY1 <= KEY; end end endmodule  


Essentially the code is meant to let me output characters by pressing the buttons on the board. When I load this onto the board and press the reset button, I enter into the Ubuntu terminal: 


sudo cat /dev/ttyUSB0 


to retrieve the output from the serial port (I am connecting through a USB converter, which think may be part of the problem, but I believe I have set that up properly) 


When I press the button the board, characters appear in the terminal as expected, but the characters are all &#65533; (the ascii replacement character). No matter what I've tried I cannot get the computer to output anything else. Any suggestions are welcome.
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