ptos.v

USB audio card 音效卡設計原理圖,說明及源碼

module PTOS(clk,par_in,int_mcu,serial,bclk,sync,cpld_rst,codec_rst,fmt0,fmt1,fmt2,mcu_ctrl) ;

input clk;
input mcu_ctrl;
input [15:0]par_in ;
output serial;
output sync;                     //44.1KHZ to CODEC
output bclk;                      
output int_mcu;               //88.2KHZ to MCU
input cpld_rst;
output codec_rst;
output fmt0,fmt1,fmt2;


reg bclk;
reg serial;
reg sync;
reg[15:0]par;
reg [3:0]count;
reg [3:0]fd;
reg d_syn;


assign codec_rst=cpld_rst;
assign fmt0=(mcu_ctrl==0)?par_in[0]:1;
assign fmt1=(mcu_ctrl==0)?par_in[1]:1;
assign fmt2=(mcu_ctrl==0)?par_in[2]:1;
assign int_mcu=!d_syn;

initial begin fd=0;end
// add your declarations here
always @(posedge clk)
begin
			  fd<=fd+1;
		   if(fd==7) fd<=0;
		   if(fd<4) bclk<=0;
			else  bclk<=1;
		
end

always @(negedge bclk)
begin
           count<=count+1;
    	     d_syn<=!count[3];	  	          //BLCK/16=88.2K HZ    d_syn 

           case (count[3:0])
        
           4'b0000:  serial<=par[15];
           4'b0001:  serial<=par[14];
           4'b0010:  serial<=par[13];
           4'b0011:  serial<=par[12];
           4'b0100:  serial<=par[11];
           4'b0101:  serial<=par[10];
           4'b0110:  serial<=par[9];
           4'b0111:  serial<=par[8];
           4'b1000:  serial<=par[7];
           4'b1001:  serial<=par[6];
           4'b1010:  serial<=par[5];
           4'b1011:  serial<=par[4];
           4'b1100:  serial<=par[3];
           4'b1101:  serial<=par[2];
           4'b1110:  serial<=par[1];
           4'b1111: begin 
                            serial<=par[0];
                   			  par<=par_in;
                            end
           endcase 
         
// add your code here
end


always @(posedge d_syn)                //sync = int_mcu/2  =88.2K/2=44.1KHZ
sync<=!sync;
endmodule