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  3. I am using FreePDK45nm library. I couldn't synthesise a...

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I am using FreePDK45nm library. I couldn't synthesise a register file.

Thommandram
Thommandram over 13 years ago

Hello,

I am doing a microprocessor design. Sap-1 architecture. I've attached the verilog codes of this microprocessor here.

The problem is.. I couldn't finish the logic synthesis of  the processor. During synthesis in the Cadence RTL compiler-Physical, the the synthesis stops at one point. At this point, the gui window status bar shows "computing design", and the terminal window shows "accessing module mem16K or reading varible mem" But the software gets hanged at this point.

The problem maybe with the memory/register file structures, I'm not sure. I want to know whether the library FreePDK45nm might be the problem (I've tried a Nangate library too!, it isn't working with that either.). 

Do you think the FreePDK45nm has the correct memory cells to implement a register file? If so, What else would be the problem in synthesizing a register file.

 

 

code for the memory block or the RAM in the microprocessor.

 

*/

module mem16K(data, address, CS, WE, OE);

  parameter wordSize = 8;

  parameter addressSize = 4;

 

  inout [wordSize-1:0] data;

  input [addressSize-1:0] address;

  input CS, WE, OE;

 

  reg [wordSize-1:0] dataReg;

  reg [wordSize-1:0] memory [0:1<<addressSize];

 

  // attach a tristate buffer to the databus

  // if OE is active(low), connect datawires to the dataRegisters

  // if OE is inactive(high), set datawires to high impedance for input

 

  assign data = (!OE && WE && !CS)?dataReg:8'hzz;

 

  // the reason cs is not put in the condition is

  // internal wires are in accordance with databus

  // but the data is not stored in memory so no problem

 

  initial

  begin

/* execution of a small program */

memory[0] = 8'h09; // LDA 9H

memory[1] = 8'h1A; // ADD AH

memory[2] = 8'h1B; // ADD BH

memory[3] = 8'h2C; // SUB CH

memory[4] = 8'hE0; // OUT

memory[5] = 8'hF0; // HLT

 

  // dataReg = 8'h00;

// Instructions must be stored here before running SAP1

// memory[0] = 8'b00001011; // LDA 08H ( ie: load contents from memory loc. 8 (B8) to acc)

// memory[1] = 8'b11100000;

// memory[2] = 8'b00011000;

// memory[3] = 8'b11100000;

//memory[2] = 8'b00001010;

//memory[3] = 8'b00001011;

//memory[2] = 8'b00011001; // ADD 09H 

//memory[2] = 8'b00011011;

 

// data contents of memory

memory[9] = 8'h01;

memory[10] = 8'h02;

memory[11] = 8'h03;

memory[12] = 8'h04;

 

  end

  

  always @(WE or OE or CS)

  begin

    // incase of active(low) CS and active(low) WE

    if (!CS && !WE)  

    begin

      #1;

      memory[address] = data;

//      $display(data);

    end

  end

 

  always @(WE or OE or CS)

  begin

      if (!OE && !CS && WE)

        dataReg = memory[address];

  end

endmodule

 

 

do you see any problem with this block? But I am able to simulate this code in the xilinx ise.. I'm just not able to do the synthesis.. help!! 

 

Thanks in advance. 

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  • grasshopper
    grasshopper over 13 years ago
    HI Thommandram, looks like you are reading the behavioral model of the register files which is intended for your functional simulations. For synthesis, you need a liberty model (.lib) for them gh-
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  • grasshopper
    grasshopper over 13 years ago
    HI Thommandram, looks like you are reading the behavioral model of the register files which is intended for your functional simulations. For synthesis, you need a liberty model (.lib) for them gh-
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