What I did Wrong in my Verilog Project? (Quartus cannot compile it)

I found a construct in your code, that's absolutely not synthesizable. You can't built a counter without a clock (a posedge or negedge condition).

always @(LocData1)
begin
  if(DeMuxCounter)
  begin
    DeMuxCounter<=DeMuxCounter+1;

You should check, what you want to achieve here and find a clear synchronous construct for it. I also noticed ripple clocks in the design that may prevent timing closure.

You mentioned a input clock speed of 400 MHz. Do you mean that InReady is 400 MHz or 200 MHz?

I don't see at once an asynchronous read of RingData. I wonder, if it has to do with usage of blocking assignments. Altera RAM interference examples are exclusively using non-blocking assignments, according to it's synchronous function. Or you have removed the problem when simplyfying the code.

In any case, without forcing RAM inference for the large buffer structure, the design can't compile I fear.

Dear FvM,

thank you for your kind suggestions. I tried to rewrite everything according to your suggestions and got my project compiled, however I am still not sure that everything is ok.

I got very impressive Fmax counts for several clocks of my design: 438MHz for InReady and 153MHz for the internal clock which is 4 times demux of InReady, so, I need at least 100MHz. Indeed I have two designs, one is running with InReady clocked at 200MHz and one other slightly differ with more wider reg [27:0] InData running at 400MHz clock.

What I cannot understand right now in my Quartus compilation, is the following: I allocate reg [63:0] RingData [0:8191], so, it is 512KBits, however, in "Flow Summary" I used zero bits.

Would enybody comment me where my RingData and TimeStep arrays was allocated? In RTL it is marked as sync_ram, but if the internal Cyclone 3 memory of 608K were used, why the Flow Summary has zero bits of usage.

I am attaching complete code of this project, RTL, Fmax and Flow summaries.

Sincerely,

Ilghiz

module My_First_Project (InData, InReady, OutClock, OutData);
parameter MaxK=8;
parameter BLKSIZE=1024;
parameter MaxN=MaxK*BLKSIZE;
input   InData;
input  InReady, OutClock;
output OutData;
reg    OutData;
reg signed  LD0, LD1, LD2, LD3, LD4;
reg signed  PE, NE;
reg  DeMuxCounter;
reg  H00, H01, H02, H03, H04, H05, H06, H07, H08, H09;
reg  H10, H11, H12, H13, H14, H15, H16, H17, H18, H19;
reg  H20, H21, H22, H23, H24, H25, H26, H27, H28, H29;
reg  H30, H31, H32, H33, H34, H35, H36, H37, H38, H39;
reg  SumS1, SumS2;
reg  LevelS1, LevelS2;
reg signed  x1, x2, x3, x4;
reg  y1, y2, y3, y4, yy1, yy2, yyy, LS1, LS2;
reg  z1, z2, z3, z4, zz1, zz2, zzz;
reg  NadoT;
reg  CurTime;
reg  RingData ;
reg  TimeStep ;
reg  BeginPos;
reg  EndPos;
reg  CurShiftData;
reg   CurPos;
reg        EndPosSw;
initial
begin
  LD4<=0;
  CurTime=0;
  SumS1=1;
  SumS2=1;
  LevelS1=1;
  LevelS2=1;
  NadoT=0;
  DeMuxCounter=0;
  BeginPos=0;
  EndPos=0;
  CurPos=79;
  EndPosSw=1;
end
always @(posedge InReady)
begin
  PE <= {PE, InData};
end
always @(negedge InReady)
begin
  NE <= {NE, InData};
  DeMuxCounter<=DeMuxCounter+1'b1;
end
always @(posedge DeMuxCounter)
begin
  if(NadoT)
  begin
    RingData=H39;
    NadoT=NadoT-1'b1;
    if(BeginPos==0) TimeStep]=CurTime;
    BeginPos=BeginPos+1'b1;
  end
  begin
    LD0<=LD4;
    LD1<={PE, NE, PE, NE, PE, NE, PE, NE,
          PE, NE, PE, NE, PE, NE, PE, NE};
    LD2<={PE, NE, PE, NE, PE, NE, PE, NE,
          PE, NE, PE, NE, PE, NE, PE, NE};
    LD3<={PE, NE, PE, NE, PE, NE, PE, NE,
          PE, NE, PE, NE, PE, NE, PE, NE};
    LD4<={PE, NE, PE, NE, PE, NE, PE, NE,
          PE, NE, PE, NE, PE, NE, PE, NE};
  end
  begin
    {H00, H01, H02, H03, H04, H05, H06, H07, H08, H09,
     H10, H11, H12, H13, H14, H15, H16, H17, H18, H19,
     H20, H21, H22, H23, H24, H25, H26, H27, H28, H29,
     H30, H31, H32, H33, H34, H35, H36, H37, H38, H39} <=
    {LD1, LD2, LD3, LD4,
     H00, H01, H02, H03, H04, H05, H06, H07, H08, H09,
     H10, H11, H12, H13, H14, H15, H16, H17, H18, H19,
     H20, H21, H22, H23, H24, H25, H26, H27, H28, H29,
     H30, H31, H32, H33, H34, H35, H36, H37, H38};
    x1<=LD0-LD1;
    x2<=LD1-LD2;
    x3<=LD2-LD3;
    x4<=LD3-LD4;
    y1<=LD1*LD1;
    y2<=LD2*LD2;
    y3<=LD3*LD3;
    y4<=LD4*LD4;
 
    SumS1<=SumS1-(SumS1>>3);
    SumS2<=SumS2-(SumS2>>3);
 
    LS1<=LevelS1-(LevelS1>>3);
    LS2<=LevelS2-(LevelS2>>3);
    CurTime<=CurTime+1;
  end
 
  begin
    z1<=x1*x1;
    z2<=x2*x2;
    z3<=x3*x3;
    z4<=x4*x4;
    yy1<=y1+y2;
    yy2<=y3+y4;
  end
 
  begin
    zz1<=z1+z2;
    zz2<=z3+z4;
    yyy<=yy1+yy2;
  end
 
  begin
    zzz<=zz1+zz2;
    SumS1<=SumS1+(yyy>>5);
  end
  begin
    SumS2<=SumS2+(zzz>>5);
  end
 
  begin
    if(SumS1>=LevelS1 && SumS2>=LevelS2)
    begin
      LevelS1<=LS1+(SumS1>>5);
      LevelS2<=LS2+(SumS2>>5);
      NadoT<=NadoT+3072;
    end
  end
end
always @(OutClock)
begin
  begin
    {CurShiftData, OutData}<=CurShiftData;
  end
  if(CurPos) CurPos<=CurPos-1'b1;
  else
  begin
    CurPos<=79;
    CurShiftData<=EndPos;
    if(EndPos==0 && EndPosSw)
    begin
      CurShiftData=TimeStep];
      EndPosSw=0;
    end
    else
    begin
      CurShiftData=RingData;
      EndPosSw=1;
      EndPos=EndPos+1'b1;
    end
  end
end
endmodule

You have several issues in the below code:

- it's combinational (no edge sensitive condition)

- CurShiftData is the RAM output register and a shift register at the same time. That doesn't work.

Because I don't know what you actually wan to achieve here, I can't suggest a solution.

always @(OutClock)
begin
  begin
    {CurShiftData, OutData}<=CurShiftData;
  end
  if(CurPos) CurPos<=CurPos-1'b1;
  else
  begin
    CurPos<=79;
    CurShiftData<=EndPos;
    if(EndPos==0 && EndPosSw)
    begin
      CurShiftData=TimeStep];
      EndPosSw=0;
    end
    else
    begin
      CurShiftData=RingData;
      EndPosSw=1;
      EndPos=EndPos+1'b1;
    end
  end
end

Dear FvM,

thank you for your reply. Actually, I really cannot guess what to do, I am new in FPGA... I need to implement the following algorithm:

on posetive or on negative edges I should send one bit from 80 bit array CurShiftdata;

if there is no data available on CurShiftData, I need to generate CurShiftData according to the following rules:

[79:75] are zeros,

[76:64] bits corresponds to EndPos, (I am using [79:64]<=EndPos am I right?)

the rest [63:0] 64 bit data are collected 1/1024 times from TimeStep array, and on other cases from RingData.

Actually, I have no filling what your comment about RAM output register means. Yes, I understand that it is shift register, and probably it is by some means also RAM, but when it is RAM or not, I cannot define myself, so I cannot figure out how to fix this problem. Please, help me!

Sincerely,

Ilghiz

As a general remark, your code is rather complex for a "First_Project". I hope, you're able to solve the involved problems without too much frustration. Most people start learning HDL programming with more basic design problems.

--- Quote Start ---

on positive or on negative edges I should send one bit

--- Quote End ---

I understand now, why you wrote always @(outclock), but unfortunately, it's not synthesizable. You need a kind of DDIO (dual-data-rate) output register. I present a principle solution in the code snippet below (registering two bits and use a multiplexer to select the right output data bit for both clock phases), for high OutClock speeds, explicite instantiation of a DDIO primitive may be required.

The other point is to keep the requirements for RAM inference. I'm showing below a construct that is accepted by the Quartus compiler, but I'm not sure if it's acceptable to register the RAM output 1 clock cycle in advance. If it doesn't work this way, you have to use a different construct, that reserves one clock cycle delay for the RAM read action.

always @(posedge OutClock)
begin
  begin
    {CurShiftData, OutData_n,OutData_p}<=CurShiftData;
  end
  if(CurPos)
  begin 
    CurPos=CurPos-1'b1;
  end
  else
  begin
    CurPos<=79;
    CurShiftData<=EndPos;
    if(EndPos==0 && EndPosSw)
    begin
      EndPosSw<=0;
      CurShiftData<=CurShiftData_s1;
    end
    else
    begin
      EndPosSw<=1;
      EndPos<=EndPos+1'b1;
      CurShiftData<=CurShiftData_s2;
    end
  end
  CurShiftData_s1<=TimeStep];
  CurShiftData_s2<=RingData;
end
assign OutData = (OutClock)?OutData_p:OutData_n;

Dear FvM,

thank you very much for your kind suggestion. Due to your help and helps in other forums I was able to rewrite this example such a way that it compile and looks reasonable in RTL.

In regards to "My_Frist_Project" it is really my first project, I never used Verilog/VHDL or other synthes languages before, however, it is really simple algorithm regarding to my goal - QR like algorithm. Hope that my experience in numerical mathematics helps me to implement it fast enough :)

Sincerely,

Ilghiz