Subversion Repositories uart2bus

// a short script to calaculate the baud rate generation parameters for the

// UART to Bus core

mode(-1)

// define the GCD function since Scilab prefers to use a different function as gcd

function x = gcdn(a,b)

x = zeros(length(b),length(a));

for n=1:length(a),

        for m=1:length(b),

                x=a(n);

                y=b(m);

                while y~=0

                        r=modulo(x,y);

                        x=y;

                        y=r;

                end

                x(m,n) = x;

        end

end

endfunction

// request the required clock rate and baud rate parameters

dig_labels = ["Clock Frequency in MHz"; "UART Baud Rate in bps"];

default_val = ["40"; "115200"];

params = evstr(x_mdialog("Enter Core Parameters", dig_labels, default_val));

// extract the parameters

global_clock_freq = params(1)*1e6;

baud_rate = params(2);

// calculate the baud rate generator parameters

D_BAUD_FREQ = 16*baud_rate / gcdn(global_clock_freq, 16*baud_rate);

D_BAUD_LIMIT = (global_clock_freq / gcdn(global_clock_freq, 16*baud_rate)) - D_BAUD_FREQ;

// print the values to the command window

printf("Calculated core baud rate generator parameters:\n");

printf("    D_BAUD_FREQ  = 12''d%d\n", D_BAUD_FREQ);

printf("    D_BAUD_LIMIT = 16''d%d\n", D_BAUD_LIMIT);

// open a message with the calculated values

mes_str = ["Calculated core baud rate generator parameters:"; ...

           "    D_BAUD_FREQ  = "+string(D_BAUD_FREQ); ...

           "    D_BAUD_LIMIT = "+string(D_BAUD_LIMIT); ...

           ""; ...

           "The verilog definition can be copied from the following lines:"; ...

           "`define D_BAUD_FREQ  12''d"+string(D_BAUD_FREQ); ...

           "`define D_BAUD_LIMIT 16''d"+string(D_BAUD_LIMIT);

           ];

messagebox(mes_str);