I am trying to assign ADDR to pcOut but ADDR is showing up as xxxxxxxx in GTKWave.
Here is my code:
module processor (
input CLK,
// Memory
input [31:0] DATAOUT, // Memory data out
output [31:0] DATAIN, // Memory data in
output [31:0] ADDR, // Memory address
output WE // Memory write enable
);
wire [3:0] aluSel;
wire [4:0] regSel1, regSel2, regDataSel;
wire regLoad, aluEnable, pcLoad, pcNext;
wire [31:0] regDataIn, regDataOut1, regDataOut2, aluOut, pcOut, pcIn, aluA, aluB;
assign ADDR = pcOut;
controlUnit controlUnit (
.CLK(CLK), // Clock
// Outputs
.memDataOut(DATAOUT),
.regDataOut1(regDataOut1),
.regDataOut2(regDataOut2),
.aluOut(aluOut),
.pcOut(pcOut),
// Load and enable
.pcLoad(pcLoad),
.regLoad(regLoad),
.aluEnable(aluEnable),
.pcNext(pcNext),
// Selects
.aluSel(aluSel),
.regSel1(regSel1),
.regSel2(regSel2),
.regDataSel(regDataSel),
// Inputs
.pcIn(pcIn),
.regDataIn(regDataIn),
.aluA(aluA),
.aluB(aluB),
.memDataIn(DATAIN),
.memAddr(ADDR)
);
datapath datapath (
.pcNext(pcNext),
// Load and enable
.pcLoad(pcLoad),
.regLoad(regLoad),
.aluEnable(aluEnable),
// Selects
.aluSel(aluSel),
.regSel1(regSel1),
.regSel2(regSel2),
.regDataSel(regDataSel),
// Inputs
.regDataIn(regDataIn),
.pcIn(pcIn),
.aluA(aluA),
.aluB(aluB),
// Outputs
.regDataOut1(regDataOut1),
.regDataOut2(regDataOut2),
.aluOut(aluOut),
.pcOut(pcOut)
);
endmodule
Can anyone help?
Thanks in advance.
Edit:
pcOut is outputting the correct value but ADDR is not being set that same value.
Edit 2:
Here is the code for the controlUnit module:
module controlUnit (
input CLK,
input [31:0] memDataOut, regDataOut1, regDataOut2, aluOut, pcOut,
output reg [0:0] pcLoad, regLoad, aluEnable, pcNext,
output reg [3:0] aluSel,
output reg [4:0] regSel1, regSel2, regDataSel,
output reg [31:0] pcIn, regDataIn, aluA, aluB, memDataIn, memAddr
);
reg cycle = 0;
wire [10:0] opcode;
wire [4:0] rs1, rs2, rd;
decoder decoder (
.cycle(cycle),
.instruction(memDataOut),
.rs1(rs1),
.rs2(rs2),
.rd(rd),
.opcode(opcode)
);
always #(posedge CLK) begin
case (cycle)
1'b0: begin
regLoad <= 0;
aluEnable <= 0;
pcNext <= 0;
end
1'b1: begin
pcNext <= 1;
case (opcode)
11'b00000110011: begin // Add
regSel1 <= rs1;
regSel2 <= rs2;
regDataSel <= rd;
aluSel <= 0;
aluEnable <= 1;
regDataIn <= aluOut;
regLoad <= 1;
end
11'b10000110011: begin // Sub
end
endcase
end
endcase
cycle <= !cycle;
end
endmodule
Your controlUnit doesn't seem to have any logic attached to memAddr, but memAddr is still an output of controlUnit. At the top level, you port map ADDR to .memAddr, and you also assign ADDR = pcOut. You're trying to drive ADDR in two different locations.
Related
I have created the following module for Data_Mem:
module Data_Mem(
input clk,
input memWrite,
input [5:0] addr,
input [31:0] writeData,
output [31:0] readData
);
reg [31:0] readData;
reg [31:0] addrSpace [0:63];
integer i;
initial begin
for (i=0;i<64;i=i+1)
addrSpace[i] = 0;
end
always # (*) begin
if (memWrite == 1)
begin
addrSpace[addr] <= writeData;
end
readData <= addrSpace[addr];
end
endmodule
Now, I have written the following testbench to see if I can get values to stay in a specified location or address. The testbench is as follows:
reg [5:0] addr;
reg [31:0] writeData;
reg memWrite, clk;
wire [31:0] readData;
//
Data_Mem datamem_testUnit1(.clk(clk), .memWrite(memWrite), .writeData(writeData), .readData(readData));
initial
begin
#10 a = 6'b001111; writeData = 32'h000A; memWrite = 0;
#10 a = 6'b000001; writeData = 32'h000C; memWrite = 1;
#10 a = 6'b000001;
#10 $finish;
end
endmodule
For the simulation results, I see that its taking in my desired values just fine, but dataRead is just XXXX for the whole time. I have included a second addr 00011 as to see whether this result is because of any sort of overlap while writing, but I do not see the desired "000C" for readData even when the addr is still declared as 000001. Please help!
I have included a screenshot of my simulation results.
It looks like you simply forgot to connect the addr signal in your testbench to the addr port of your Data_Mem module. Try
Data_Mem datamem_testUnit1(.clk(clk), .memWrite(memWrite), .addr(addr), .writeData(writeData), .readData(readData));
Also, your always-block will infer latches. I think you probably want it to be clocked, like this:
always # (posedge clk) begin
This involves having to drive the clk port in your testbench, however.
parameter N1 = 5;
parameter N2 = 5;
wire [(N1+N2-1):0] seckey [8:1];
shiftreg #(.depth(N1+N2-1)) sr1( .clk(clk), .reset(reset), .data_in(muxout[1]), .data_out(seckey[0]));
//--------------------------------------------------------------------------//
module shiftreg(
input clk,
input reset,
input data_in,
output data_out
);
parameter depth = 9;
wire [depth:0] connect_wire;
wire [depth:0] data_out;
//wire [depth:0] data_out;
assign connect_wire[0] = data_in;
assign data_out[depth:0] = connect_wire[depth:0];
genvar i;
generate
for(i=1; i<=depth; i=i+1) begin: loop1
ff dff(.d(connect_wire[i-1]), .clk(clk), .reset(reset), .q(connect_wire[i]));
end
endgenerate
endmodule
//--------------------------------------------------------------------//
module ff(
input d,
input clk,
input reset,
output reg q
);
always # (posedge clk or posedge reset)
begin
if (reset) begin
q <= 1'b0;
end
else begin
q <= d;
end
end
endmodule
//------------------------------------------------------------------------//
Value of N1 and N2 is 5.
I am getting the error "Size mismatch in connection of port (data_out). Formal port size is 10-bit while actual signal size is 1-bit"
I have set the size of the data_out port to be 10 bits but its still showing the signal size to be 1 bit.
To set the size of data_out, you need to set the size where you declare the parameter. Try the header below
module shiftreg(clk, reset, data_in, data_out);
parameter depth = 9;
input clk;
input reset;
input data_in;
input [depth:0] data_out;
Also:
assign data_out[depth:0] = connect_wire[depth:0];
can be replaced with
assign data_out = connect_wire;
My current task is to create a memory driver. The specific issue is that I have a shift register designed to concatenate four 8-bit words into one 32-bit and then send that to the output. The module works when being simulated by itself but it fails to respond when connected to other modules. Here's the code :
The shift register code :
module shiftReg (
data_8,
clk,
valid1,
rstn,
data_32,
valid_fifo,
count,
REGA,
REGB,
REGC,
REGD
);
input wire [7:0] data_8;
input wire valid1;
input wire clk;
input wire rstn;
output reg [31:0] data_32;
output reg valid_fifo;
output reg [3:0] count;
output reg [7:0] REGA;
output reg [7:0] REGB;
output reg [7:0] REGC;
output reg [7:0] REGD;
initial
begin
count <= 4'b0001;
REGA <= 8'b0;
REGB <= 8'b0;
REGC <= 8'b0;
REGD <= 8'b0;
valid_fifo <= 1'b0;
end
always #(posedge valid1)
begin
if(~rstn)
begin
count = 4'b0001;
REGA = 0;
REGB = 0;
REGC = 0;
REGD = 0;
end
else if(valid1 == 1'b1)
begin
case (count)
4'b0001: REGA = data_8;
4'b0010: REGB = data_8;
4'b0100: REGC = data_8;
4'b1000: REGD = data_8;
endcase
valid_fifo = 1'b0;
end
if(count == 4'b1000)
begin
data_32 = {REGD,REGC,REGB,REGA};
valid_fifo = 1'b1;
count = 4'b0001;
end
else
begin
count = count << 1;
end
end
endmodule
The module where I am instantiating it is called altogether.
Here is the code :
module altogether (
input wire BUTTON_AT,
input wire CLK_AT,
input wire RSTN_AT,
output wire MEM_FULL_AT,
output wire EMPTY_AT,
inout wire VALID_IN_AT,
inout wire [7:0] DATA_8_AT,
inout wire VALID1_AT,
inout wire [31:0] DATA_32_AT,
inout wire STOP_AT,
inout wire VALID_FIFO_AT,
inout wire [31:0] DATA_AT,
inout wire WR_AT,
inout wire [6:0] ADDR_AT,
output wire [7:0] REG_A_AT,
output wire [7:0] REG_B_AT,
output wire [7:0] REG_C_AT,
output wire [7:0] REG_D_AT,
output wire [3:0] COUNT_AT
);
shiftReg shift_register (
.data_8(DATA_8_AT),
.clk(CLK_AT),
.valid1(VALID_1_AT),
.rstn(RSTN_AT),
.data_32(DATA_32_AT),
.valid_fifo(VALID_FIFO_AT),
.REGA(REG_A_AT),
.REGB(REG_B_AT),
.REGC(REG_C_AT),
.REGD(REG_D_AT),
.count(COUNT_AT)
);
For some reason, the valid == 1'b1 condition is not executed when I put the shift register along with everything else. I have really run out of ideas, hope someone manages to look at it and give me an insight.
Somewhere during synthesis you probably got warning that you're using VALID_1_AT signal, which has no driver. That's because in altogether module declaration you define VALID1_AT signal (notice _ missing in signal name). That's why valid1 in your shift register is not driven at all.
You should change:
.valid1(VALID_1_AT)
into:
.valid1(VALID1_AT)
to make it works.
Hi i am using the folowing code to design a n-bit counter.
Depending on the start and end i want to instantiate up or down counter.
But i am getting "Malformed statement". Please help.
module nbitUpCounter(startc,endc , clk, rst_n,actlow,count);
parameter n = 7;
output reg [n:0] count;
input [n:0] startc;
input [n:0] endc;
input clk;
input rst_n;
input actlow;
// Increment count on clock
always #(actlow or posedge clk or negedge rst_n)
begin
if (actlow == 0)
begin
if (rst_n==0)
count = startc;
else if (count==endc) count=startc;
else count = count + 1;
end
end
endmodule
module nbitDownCounter(startc,endc , clk, rst_n,actlow,count);
parameter n = 7;
output reg [n:0] count;
input [n:0] startc;
input [n:0] endc;
input clk;
input rst_n;
input actlow;
// Increment count on clock
always #(actlow or posedge clk or negedge rst_n)
begin
if (actlow == 0)
begin
if (rst_n==0)
count = startc;
else if (count==endc) count=startc;
else count = count - 1;
end
end
endmodule
module Init(startc,endc , clk, rst_n,actlow,count);
parameter n = 7;
output wire [n:0] count;
input [n:0] startc;
input [n:0] endc;
input clk;
input rst_n;
input actlow;
generate
initial
begin
if(startc>endc)
nbitDownCounter c(startc, endc, C_t,rst_t,actlow,count);
end
endgenerate
endmodule
module Testbench;
reg [7:0] startc, endc;
reg C_t, rst_t;
reg actlow;
wire [7:0] outc;
initial
begin
//case 0
startc <= 8'b00000011; endc <= 8'b0000001;
//Init i(startc,endc,C_t,rst_t,actlow,count);
actlow<=0;
C_t <=1; rst_t <=0;
#1 $display("count = %b",outc );
//case1
rst_t<=1;C_t<=0;C_t<=1;
#1 $display("count = %b",outc );
//Case3
C_t<=0;C_t<=1;
#1 $display("count = %b",outc );
//Case3
C_t<=0;C_t<=1;
#1 $display("count = %b",outc );
end
endmodule
You're trying to instantiate your module in an initial block, which is illegal. Removing the initial begin inside module Init should solve the problem. Have a look at this page for an example: http://asic-soc.blogspot.de/2012/06/verilog-hdl-generate-blocks.html
Our assignment is to build a rudimentary single-cycle CPU in Verilog, but I'm not getting even more fundamental modules of it correct. For instance, to test the Instruction Memory module, we've been given a text file "hw3Test.txt" with instructions in hex, and I'm trying to slurp that into the IM.
00221820
AC010000
8C240000
10210001
00001820
00411822
When I run a testbench, I see that the only instructions that get into memory are the second, third, and fourth lines. Here's the IM module:
module IM(addr, clk, inst);
input [31:0] addr;
input clk;
output reg [31:0] inst;
reg [31:0] mem [255:0];
initial begin
$readmemh("hw3Test.txt", mem);
end
always #( posedge clk) begin
inst=mem[addr[31:2]];
end
endmodule
And the testbench:
module imtest;
// Inputs
reg [31:0] addr;
reg clk;
// Outputs
wire [31:0] inst;
// Instantiate the Unit Under Test (UUT)
IM uut (
.addr(addr),
.clk(clk),
.inst(inst)
);
initial begin
// Initialize Inputs
addr = 0;
clk = 0;
// Wait 100 ns for global reset to finish
#100;
// Add stimulus here
clk = 0;
addr = 0;
#100;
forever begin
#20;
clk = ~clk;
addr = addr + 4;
end
end
endmodule
I'm also not sure I'm even getting the PC-to-IM module correct, because aside from the initialized values, everything but the rst and clk signals show no valid values. Can anyone point out where I'm going wrong?
module pc_im(
// Inputs
rst, clk, PCin,
// Outputs
inst, PCout
);
input clk, rst;
input [31:0] PCin;
output reg [31:0] inst;
output reg [31:0] PCout;
PC mypc (
.clk(clk),
.rst(rst),
.PCin(PCin),
.PCout(PCout)
);
IM myim(
.clk(clk),
.addr(PCout),
.inst(inst)
);
endmodule
Here's the PC.v module:
module PC(rst, clk, PCin, PCout);
input clk, rst;
input [31:0] PCin;
output reg [31:0] PCout;
always #(posedge clk) begin
if (rst) PCout <= 0;
else PCout <= PCin + 4;
end
endmodule
And finally, the testbench:
module pcimtest;
// Inputs
reg rst;
reg clk;
reg [31:0] PCin;
// Outputs
wire [31:0] inst;
wire [31:0] PCout;
// Instantiate the Unit Under Test (UUT)
pc_im uut (
.rst(rst),
.clk(clk),
.PCin(PCin),
// Outputs
.inst(inst),
.PCout(PCout)
);
initial begin
// Initialize Inputs
rst = 1;
clk = 0;
PCin = 0;
// Wait 100 ns for global reset to finish
#100;
rst = 0;
forever begin
#100;
clk <= ~clk;
PCin <= PCout;
end
// Add stimulus here
end
endmodule
Here are a few things that look suspect.
Problem 1
It is normally good to use non-blocking assignments in blocks intended to infer registers.
i.e. change
always #( posedge clk) begin
inst=mem[addr[31:2]];
end
to
always #( posedge clk) begin
inst<=mem[addr[31:2]];
end
Problem 2
You are changing signals twice per clock cycle, once on negative edge and once on positive edge.
Change:
forever begin
#20;
clk = ~clk;
addr = addr + 4;
end
to
forever begin
#20;
clk = 1;
#20;
clk = 0;
addr = addr + 4;
end
Problem 3
You are using synchronous resets but not supplying a clock during reset.
Consider the code
always #(posedge clk) begin
if (rst) PCout <= 0;
else PCout <= PCin + 4;
end
This block will only activate on positive clock edges. However, you make reset high while the clock is paused so no reset will happen.
Change
rst = 1;
clk = 0;
PCin = 0;
// Wait 100 ns for global reset to finish
#100;
to
rst = 1;
clk = 0;
PCin = 0;
#20
clk = 1;
#20
clk = 0;
// Wait 100 ns for global reset to finish
#100;