DSP与FPGA间简单通信时序

DSP与FPGA采用EMIF接口通信，即将FPGA作为DSP的外部SRAM，只需设置EMIF控制的存储器为SRAM类型即可，DSP通过EMIF接口读写SRAM的时序如下: 参考datasheet《tms320dm642.pdf》 

可以根据以上时序图编写FPGA代码，以下仅供参考：

moduleDSP_FPGA(                                       
                                input clk,                            
                                input [2:0] addr,       //简单测试，没有用到所有地址             
                                 inout[15:0] data,     //16位数据宽度            
                                input CE_2,//FPGA片选                 
                                input AOE,                            
                                input AWE                             
                             );                                     
                                                                     
                                                       
reg [15:0]DSP_FPGA_REG0;                          
reg [15:0]DSP_FPGA_REG1;                              
reg [15:0]DSP_FPGA_REG2;                          
reg [15:0]DSP_FPGA_REG3;                          
reg [15:0]DSP_FPGA_REG4;                              
reg [15:0] DSP_FPGA_REG5;                          
reg [15:0]DSP_FPGA_REG6;                          
reg [15:0]DSP_FPGA_REG7;                          
                                                  

     

wire rd_en = ~CE_2 && ~AOE;

reg [15:0] data_reg;      
//always @(posedge clk) //DSP读操作,The samplingpoint of DSP reading is the risging edge ofAWE!                               
always @(*)    //这里没有用时钟，用的latch
begin                                                
  if(rd_en)                                 
     begin                                           
       case(addr[2:0])                              
         3'd0   : data_reg <= DSP_FPGA_REG0;  
         3'd1   : data_reg <= DSP_FPGA_REG1;  
         3'd2   : data_reg <= DSP_FPGA_REG2;  
         3'd3   : data_reg <= DSP_FPGA_REG3;  
         3'd4   : data_reg <= DSP_FPGA_REG4;  
         3'd5   : data_reg <= DSP_FPGA_REG5;  
         3'd6   : data_reg <= DSP_FPGA_REG6;  
         3'd7   : data_reg <= DSP_FPGA_REG7;       
         default: ;                                 
        endcase                                 
    end                                                                                               
end                                              

      
      
reg AWE_tmp1;
reg AWE_tmp2;
always @(posedge clk)
begin
     AWE_tmp1 <= AWE;
     AWE_tmp2 <= AWE_tmp1;
end      
      
wire AWE_RISING = ~AWE_tmp2 && AWE_tmp1;//与clk同步  

     
always@(*)                                   
begin                                        
  if(AWE_RISING)      //这里也没有用时钟，用的是latch                       
    begin                                    
       case(addr[2:0])                       
         3'd0   : DSP_FPGA_REG0 <= data; 
         3'd1   : DSP_FPGA_REG1 <= data; 
         3'd2   : DSP_FPGA_REG2 <= data; 
         3'd3   : DSP_FPGA_REG3 <= data; 
         3'd4   : DSP_FPGA_REG4 <= data; 
         3'd5   : DSP_FPGA_REG5 <= data; 
         3'd6   : DSP_FPGA_REG6 <= data; 
         3'd7   : DSP_FPGA_REG7 <= data;    
         default: ;                          
        endcase                          
    end                                      
end                                         

assign data =  rd_en ? data_reg : 16'hzzzz;
      
endmodule


//////////////////////////////////////////////////////////
DSP(具体为DM642)端程序：寄存器设置参考 《EMIF ReferenceGuide- spru266b.pdf》 即spru266

#define   FPGA_ADDR             0xA0000000  
//#define   EMIFA_GBLCTL         0x01800000
#define   EMIFA_CECTL2         0x01800010 

//#define   EMIFA_CESEC2        0x01800050  

void  delay(unsigned long time)
{
       unsigned long i;
       for(i = 0; i < 1000; i++)
       {
            for(; time >0 ; time--)
             {
             } 
        }
 }

unsigned short write_value = 0;
unsigned short read_value = 0; 
int main(void)
{
        unsigned short *ptr;

        *(unsigned volatile int *)EMIFA_CECTL2 =(unsigned int)0xFFFFFF13;//设置EMIF控制的存储器类型为                                                                                                                        //16位宽SRAM    

        ptr = (unsigned short*)(unsigned int)FPGA_ADDR;
        
        while(1)
        {
              *ptr = write_value;
               read_value=   *ptr;     //调试时通过观察write_value与read_value的值是否相等可以检验通信是否正常 

               delay(100000);
               write_value++;
         }
     
         return 0;
}    

 

实际测试发现写入与读出的值相同