Subversion Repositories uart2bus

//---------------------------------------------------------------------------------------

// baud rate generator for uart 

//

// this module has been changed to receive the baud rate dividing counter from registers.

// the two registers should be calculated as follows:

// first register:

//              baud_freq = 16*baud_rate / gcd(global_clock_freq, 16*baud_rate)

// second register:

//              baud_limit = (global_clock_freq / gcd(global_clock_freq, 16*baud_rate)) - baud_freq 

//---------------------------------------------------------------------------------------

module baud_gen

(

        clock, reset,

        ce_16, baud_freq, baud_limit

);

//---------------------------------------------------------------------------------------

// modules inputs and outputs 

input                   clock;          // global clock input 

input                   reset;          // global reset input 

output                  ce_16;          // baud rate multiplyed by 16 

input   [11:0]   baud_freq;      // baud rate setting registers - see header description 

input   [15:0]   baud_limit;

// internal registers 

reg ce_16;

reg [15:0]       counter;

//---------------------------------------------------------------------------------------

// module implementation 

// baud divider counter  

always @ (posedge clock or posedge reset)

begin

        if (reset)

                counter <= 16'b0;

        else if (counter >= baud_limit)

                counter <= counter - baud_limit;

        else

                counter <= counter + baud_freq;

end

// clock divider output 

always @ (posedge clock or posedge reset)

begin

        if (reset)

                ce_16 <= 1'b0;

        else if (counter >= baud_limit)

                ce_16 <= 1'b1;

        else

                ce_16 <= 1'b0;

end

endmodule

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//                                              Th.. Th.. Th.. Thats all folks !!!

//---------------------------------------------------------------------------------------