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sami47

receive 256 bits data from PS via axi lite slave

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20067734_1391199087601414_1106903305_n.png.2407228f464f600f380b14e0b5ec532d.pngHey evryone !

I'm really stuck for a few days!
I am sending 256 bits looped from my PS. But I think that I get juste the last 4 bytes of 8*4 that i send !

What I want from you is a few vhdl code line that allow me to receive all of my data (8 * 32 bits).

You will find enclosed a photo of the result that I get
 
Waiting for your reply. thank you
I send my data on register 1 and I have to store it in ram

Here a pseudo code c that allow me to send 8*32 bits:

for(int i = 0; i < 8; i++){
    Data_struct -> in = message[i] ;
 }



the vhdl code of AXI lite :


library ieee;
    use ieee.std_logic_1164.all;
    --use ieee.numeric_std.all;
    use ieee.std_logic_arith.all;
    use ieee.std_logic_unsigned.all;
    
    entity axi_lite1_v1_0_S00_AXI is
        generic (
            -- Users to add parameters here
    
            -- User parameters ends
            -- Do not modify the parameters beyond this line
    
            -- Width of S_AXI data bus
            C_S_AXI_DATA_WIDTH    : integer    := 32;
            -- Width of S_AXI address bus
            C_S_AXI_ADDR_WIDTH    : integer    := 4
        );
        port (
            -- Users to add ports here
            --input_data : in std_logic_vector(C_S_AXI_DATA_WIDTH - 1 downto 0);
    
            -- User ports ends
            -- Do not modify the ports beyond this line
    
            -- Global Clock Signal
            S_AXI_ACLK    : in std_logic;
            -- Global Reset Signal. This Signal is Active LOW
            S_AXI_ARESETN    : in std_logic;
            -- Write address (issued by master, acceped by Slave)
            S_AXI_AWADDR    : in std_logic_vector(C_S_AXI_ADDR_WIDTH-1 downto 0);
            -- Write channel Protection type. This signal indicates the
                -- privilege and security level of the transaction, and whether
                -- the transaction is a data access or an instruction access.
            S_AXI_AWPROT    : in std_logic_vector(2 downto 0);
            -- Write address valid. This signal indicates that the master signaling
                -- valid write address and control information.
            S_AXI_AWVALID    : in std_logic;
            -- Write address ready. This signal indicates that the slave is ready
                -- to accept an address and associated control signals.
            S_AXI_AWREADY    : out std_logic;
            -- Write data (issued by master, acceped by Slave)
            S_AXI_WDATA    : in std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
            -- Write strobes. This signal indicates which byte lanes hold
                -- valid data. There is one write strobe bit for each eight
                -- bits of the write data bus.    
            S_AXI_WSTRB    : in std_logic_vector((C_S_AXI_DATA_WIDTH/8)-1 downto 0);
            -- Write valid. This signal indicates that valid write
                -- data and strobes are available.
            S_AXI_WVALID    : in std_logic;
            -- Write ready. This signal indicates that the slave
                -- can accept the write data.
            S_AXI_WREADY    : out std_logic;
            -- Write response. This signal indicates the status
                -- of the write transaction.
            S_AXI_BRESP    : out std_logic_vector(1 downto 0);
            -- Write response valid. This signal indicates that the channel
                -- is signaling a valid write response.
            S_AXI_BVALID    : out std_logic;
            -- Response ready. This signal indicates that the master
                -- can accept a write response.
            S_AXI_BREADY    : in std_logic;
            -- Read address (issued by master, acceped by Slave)
            S_AXI_ARADDR    : in std_logic_vector(C_S_AXI_ADDR_WIDTH-1 downto 0);
            -- Protection type. This signal indicates the privilege
                -- and security level of the transaction, and whether the
                -- transaction is a data access or an instruction access.
            S_AXI_ARPROT    : in std_logic_vector(2 downto 0);
            -- Read address valid. This signal indicates that the channel
                -- is signaling valid read address and control information.
            S_AXI_ARVALID    : in std_logic;
            -- Read address ready. This signal indicates that the slave is
                -- ready to accept an address and associated control signals.
            S_AXI_ARREADY    : out std_logic;
            -- Read data (issued by slave)
            S_AXI_RDATA    : out std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
            -- Read response. This signal indicates the status of the
                -- read transfer.
            S_AXI_RRESP    : out std_logic_vector(1 downto 0);
            -- Read valid. This signal indicates that the channel is
                -- signaling the required read data.
            S_AXI_RVALID    : out std_logic;
            -- Read ready. This signal indicates that the master can
                -- accept the read data and response information.
            S_AXI_RREADY    : in std_logic
        );
    end axi_lite1_v1_0_S00_AXI;
    
    architecture arch_imp of axi_lite1_v1_0_S00_AXI is
    
        -- AXI4LITE signals
        signal axi_awaddr    : std_logic_vector(C_S_AXI_ADDR_WIDTH-1 downto 0);
        signal axi_awready    : std_logic;
        signal axi_wready    : std_logic;
        signal axi_bresp    : std_logic_vector(1 downto 0);
        signal axi_bvalid    : std_logic;
        signal axi_araddr    : std_logic_vector(C_S_AXI_ADDR_WIDTH-1 downto 0);
        signal axi_arready    : std_logic;
        signal axi_rdata    : std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
        signal axi_rresp    : std_logic_vector(1 downto 0);
        signal axi_rvalid    : std_logic;
    
        -- Example-specific design signals
        -- local parameter for addressing 32 bit / 64 bit C_S_AXI_DATA_WIDTH
        -- ADDR_LSB is used for addressing 32/64 bit registers/memories
        -- ADDR_LSB = 2 for 32 bits (n downto 2)
        -- ADDR_LSB = 3 for 64 bits (n downto 3)
        constant ADDR_LSB  : integer := (C_S_AXI_DATA_WIDTH/32)+ 1;
        constant OPT_MEM_ADDR_BITS : integer := 1;
        ------------------------------------------------
        ---- Signals for user logic register space example
        --------------------------------------------------
        ---- Number of Slave Registers 4
        signal slv_reg0    :std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
        signal slv_reg1    :std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
        signal slv_reg2    :std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
        signal slv_reg3    :std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
        signal slv_reg_rden  : std_logic;
        signal slv_reg_wren : std_logic;
        signal reg_data_out : std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
        signal byte_index : integer;
    
        constant ADDRESS_SIZE : integer := 4;
        signal address_in : std_logic_vector(ADDRESS_SIZE - 1 downto 0);
        signal ready_pl : std_logic := '0';
        signal reset : std_logic := '1';
        signal en_ram : std_logic;
        signal getPSData    : std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
        signal DataDone    : std_logic_vector(C_S_AXI_DATA_WIDTH-1 downto 0);
        signal PSenable : std_logic;
        signal PLdone : std_logic := '0';
        signal test : std_logic := '1';
        signal Count : integer :=0;
        constant width_ram : integer :=32;
        type ram_type is array (0 TO 2 ** ADDRESS_SIZE - 1) of  std_logic_vector(width_ram-1 downto 0);
        signal tmp_ram: ram_type;
        constant var : integer  :=256;



    
        
        --create component right here
    component PLprocessing is
        generic(  DATA_SIZE    : integer:=32;
                        ADDRESS_SIZE : integer :=4
                    );
        port (    
                clk                                  : in std_logic;  
                en_in                            : in std_logic;
                input_data                      : in  std_logic_vector(DATA_SIZE - 1 downto 0);
                address_in                   : in std_logic_vector(ADDRESS_SIZE -1 downto 0);
                data_out                     : out std_logic_vector(DATA_SIZE -1 downto 0);
                ready                        : out std_logic
                );
    end component PLprocessing;
    
    begin  
        -- I/O Connections assignments
        
    mmap_pl : PLprocessing
                    generic map
                        (DATA_SIZE => C_S_AXI_DATA_WIDTH,
                         ADDRESS_SIZE => ADDRESS_SIZE
                        )
                    port map(
                        clk => S_AXI_ACLK,
                        en_in => en_ram,
                        input_data => slv_reg1,
                        address_in => address_in,
                        data_out => DataDone,
                        ready => ready_pl
                        );
    
    
        S_AXI_AWREADY    <= axi_awready;
        S_AXI_WREADY        <= axi_wready;
        S_AXI_BRESP        <= axi_bresp;
        S_AXI_BVALID        <= axi_bvalid;
        S_AXI_ARREADY    <= axi_arready;
        S_AXI_RDATA            <= axi_rdata;
        S_AXI_RRESP        <= axi_rresp;
        S_AXI_RVALID        <= axi_rvalid;
        -- Implement axi_awready generation
        -- axi_awready is asserted for one S_AXI_ACLK clock cycle when both
        -- S_AXI_AWVALID and S_AXI_WVALID are asserted. axi_awready is
        -- de-asserted when reset is low.
        
        
        
        
    
        process (S_AXI_ACLK)
        begin
          if rising_edge(S_AXI_ACLK) then
            if S_AXI_ARESETN = '0' then
              axi_awready <= '0';
            else
              if (axi_awready = '0' and S_AXI_AWVALID = '1' and S_AXI_WVALID = '1') then
                -- slave is ready to accept write address when
                -- there is a valid write address and write data
                -- on the write address and data bus. This design
                -- expects no outstanding transactions.
                axi_awready <= '1';
              else
                axi_awready <= '0';
              end if;
            end if;
          end if;
        end process;
    
        -- Implement axi_awaddr latching
        -- This process is used to latch the address when both
        -- S_AXI_AWVALID and S_AXI_WVALID are valid.
    
        process (S_AXI_ACLK)
        begin
          if rising_edge(S_AXI_ACLK) then
            if S_AXI_ARESETN = '0' then
              axi_awaddr <= (others => '0');
            else
              if (axi_awready = '0' and S_AXI_AWVALID = '1' and S_AXI_WVALID = '1') then
                -- Write Address latching
                axi_awaddr <= S_AXI_AWADDR;
              end if;
            end if;
          end if;                   
        end process;
    
        -- Implement axi_wready generation
        -- axi_wready is asserted for one S_AXI_ACLK clock cycle when both
        -- S_AXI_AWVALID and S_AXI_WVALID are asserted. axi_wready is
        -- de-asserted when reset is low.
    
        process (S_AXI_ACLK)
        begin
          if rising_edge(S_AXI_ACLK) then
            if S_AXI_ARESETN = '0' then
              axi_wready <= '0';
            else
              if (axi_wready = '0' and S_AXI_WVALID = '1' and S_AXI_AWVALID = '1') then
                  -- slave is ready to accept write data when
                  -- there is a valid write address and write data
                  -- on the write address and data bus. This design
                  -- expects no outstanding transactions.           
                  axi_wready <= '1';
              else
                axi_wready <= '0';
              end if;
            end if;
          end if;
        end process;
    
        -- Implement memory mapped register select and write logic generation
        -- The write data is accepted and written to memory mapped registers when
        -- axi_awready, S_AXI_WVALID, axi_wready and S_AXI_WVALID are asserted. Write strobes are used to
        -- select byte enables of slave registers while writing.
        -- These registers are cleared when reset (active low) is applied.
        -- Slave register write enable is asserted when valid address and data are available
        -- and the slave is ready to accept the write address and write data.
        slv_reg_wren <= axi_wready and S_AXI_WVALID and axi_awready and S_AXI_AWVALID ;
    
        process (S_AXI_ACLK)
        variable loc_addr :std_logic_vector(OPT_MEM_ADDR_BITS downto 0);
        begin
          if rising_edge(S_AXI_ACLK) then
            if S_AXI_ARESETN = '0' then
              --slv_reg0 <= (others => '0');
              slv_reg1 <= (others => '0');
              slv_reg2 <= (others => '0');
              slv_reg3 <= (others => '0');
            else
              loc_addr := axi_awaddr(ADDR_LSB + OPT_MEM_ADDR_BITS downto ADDR_LSB);
              if (slv_reg_wren = '1') then
                case loc_addr is
                  when b"00" =>
                    for byte_index in 0 to (C_S_AXI_DATA_WIDTH/8-1) loop
                      if ( S_AXI_WSTRB(byte_index) = '1' ) then
                        -- Respective byte enables are asserted as per write strobes                   
                        -- slave registor 0
                        --slv_reg0(byte_index*8+7 downto byte_index*8) <= S_AXI_WDATA(byte_index*8+7 downto byte_index*8);
                      end if;
                    end loop;
                  when b"01" =>
                    for byte_index in 0 to (C_S_AXI_DATA_WIDTH/8-1) loop
                      if ( S_AXI_WSTRB(byte_index) = '1' ) then
                        -- Respective byte enables are asserted as per write strobes                   
                        -- slave registor 1
                        slv_reg1(byte_index*8+7 downto byte_index*8) <= S_AXI_WDATA(byte_index*8+7 downto byte_index*8);
                      end if;
                    end loop;
                  when b"10" =>
                    for byte_index in 0 to (C_S_AXI_DATA_WIDTH/8-1) loop
                      if ( S_AXI_WSTRB(byte_index) = '1' ) then
                        -- Respective byte enables are asserted as per write strobes                   
                        -- slave registor 2
                        slv_reg2(byte_index*8+7 downto byte_index*8) <= S_AXI_WDATA(byte_index*8+7 downto byte_index*8);
                      end if;
                    end loop;
                  when b"11" =>
                    for byte_index in 0 to (C_S_AXI_DATA_WIDTH/8-1) loop
                      if ( S_AXI_WSTRB(byte_index) = '1' ) then
                        -- Respective byte enables are asserted as per write strobes                   
                        -- slave registor 3
                        slv_reg3(byte_index*8+7 downto byte_index*8) <= S_AXI_WDATA(byte_index*8+7 downto byte_index*8);
                      end if;
                    end loop;
                  when others =>
                    --slv_reg0 <= slv_reg0;
                    slv_reg1 <= slv_reg1;
                    slv_reg2 <= slv_reg2;
                    slv_reg3 <= slv_reg3;
                end case;
              end if;
            end if;
          end if;                   
        end process;
        
        
    
    
        -- Implement write response logic generation
        -- The write response and response valid signals are asserted by the slave
        -- when axi_wready, S_AXI_WVALID, axi_wready and S_AXI_WVALID are asserted.  
        -- This marks the acceptance of address and indicates the status of
        -- write transaction.
    
        process (S_AXI_ACLK)
        begin
          if rising_edge(S_AXI_ACLK) then
            if S_AXI_ARESETN = '0' then
              axi_bvalid  <= '0';
              axi_bresp   <= "00"; --need to work more on the responses
            else
              if (axi_awready = '1' and S_AXI_AWVALID = '1' and axi_wready = '1' and S_AXI_WVALID = '1' and axi_bvalid = '0'  ) then
                axi_bvalid <= '1';
                axi_bresp  <= "00";
              elsif (S_AXI_BREADY = '1' and axi_bvalid = '1') then   --check if bready is asserted while bvalid is high)
                axi_bvalid <= '0';                                 -- (there is a possibility that bready is always asserted high)
              end if;
            end if;
          end if;                   
        end process;
    
        -- Implement axi_arready generation
        -- axi_arready is asserted for one S_AXI_ACLK clock cycle when
        -- S_AXI_ARVALID is asserted. axi_awready is
        -- de-asserted when reset (active low) is asserted.
        -- The read address is also latched when S_AXI_ARVALID is
        -- asserted. axi_araddr is reset to zero on reset assertion.
    
        process (S_AXI_ACLK)
        begin
          if rising_edge(S_AXI_ACLK) then
            if S_AXI_ARESETN = '0' then
              axi_arready <= '0';
              axi_araddr  <= (others => '1');
            else
              if (axi_arready = '0' and S_AXI_ARVALID = '1') then
                -- indicates that the slave has acceped the valid read address
                axi_arready <= '1';
                -- Read Address latching
                axi_araddr  <= S_AXI_ARADDR;           
              else
                axi_arready <= '0';
              end if;
            end if;
          end if;                   
        end process;
    
        -- Implement axi_arvalid generation
        -- axi_rvalid is asserted for one S_AXI_ACLK clock cycle when both
        -- S_AXI_ARVALID and axi_arready are asserted. The slave registers
        -- data are available on the axi_rdata bus at this instance. The
        -- assertion of axi_rvalid marks the validity of read data on the
        -- bus and axi_rresp indicates the status of read transaction.axi_rvalid
        -- is deasserted on reset (active low). axi_rresp and axi_rdata are
        -- cleared to zero on reset (active low).  
        process (S_AXI_ACLK)
        begin
          if rising_edge(S_AXI_ACLK) then
            if S_AXI_ARESETN = '0' then
              axi_rvalid <= '0';
              axi_rresp  <= "00";
            else
              if (axi_arready = '1' and S_AXI_ARVALID = '1' and axi_rvalid = '0') then
                -- Valid read data is available at the read data bus
                axi_rvalid <= '1';
                axi_rresp  <= "00"; -- 'OKAY' response
              elsif (axi_rvalid = '1' and S_AXI_RREADY = '1') then
                -- Read data is accepted by the master
                axi_rvalid <= '0';
              end if;            
            end if;
          end if;
        end process;
    
        -- Implement memory mapped register select and read logic generation
        -- Slave register read enable is asserted when valid address is available
        -- and the slave is ready to accept the read address.
        slv_reg_rden <= axi_arready and S_AXI_ARVALID and (not axi_rvalid) ;
        --DataDone <= tmp_ram(conv_integer(0));

        process (slv_reg0, slv_reg1, DataDone, slv_reg3, axi_araddr, S_AXI_ARESETN, slv_reg_rden)
        variable loc_addr :std_logic_vector(OPT_MEM_ADDR_BITS downto 0);
        begin
            -- Address decoding for reading registers
            loc_addr := axi_araddr(ADDR_LSB + OPT_MEM_ADDR_BITS downto ADDR_LSB);
            case loc_addr is
              when b"00" =>
                reg_data_out <= slv_reg0;
              when b"01" =>
                reg_data_out <= slv_reg1;
              when b"10" =>
                reg_data_out <= DataDone;
              when b"11" =>
                reg_data_out <= slv_reg3;
              when others =>
                reg_data_out  <= (others => '0');
            end case;
        end process;
    
        -- Output register or memory read data
        process( S_AXI_ACLK ) is
        begin
          if (rising_edge (S_AXI_ACLK)) then
            if ( S_AXI_ARESETN = '0' ) then
              axi_rdata  <= (others => '0');
            else
              if (slv_reg_rden = '1') then
                -- When there is a valid read address (S_AXI_ARVALID) with
                -- acceptance of read address by the slave (axi_arready),
                -- output the read dada
                -- Read address mux
                  axi_rdata <= reg_data_out;     -- register read data
              end if;   
            end if;
          end if;
        end process;
    
    
        -- Add user logic here
        
        --slv_reg0 <= slv_reg1 + slv_reg2;
        --slv_reg0 <= "01000000000000000000000000000000"; 

    
    end arch_imp;
Edited by sami47

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8 answers to this question

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@sami47,

Sigh.  That's a lot of complex code there.  I'm struggling to work through just understanding the logic.  Perhaps it's late, and I should take another look Monday morning.

For now, let me offer you a touch of perspective.  You know, lots of folks publish their code here on Digilent.  They've spent their time struggling and struggling to get their code to work, and expect that an expert can just look at it and spot the problem.  Sometimes I can.  I certainly enjoy doing that.  Usually, they are sharing something a touch simpler, though ...

Looking over your code above, I haven't spotted your bug.  Neither have I managed to get a good handle on what you've got going on while trying to access the bus.

The typical response at this point from the Digilent staff would be to point you to something that works.  Let me point you at my own example AXI component.  Maybe it will help.  If you look through that, you'll find the fundamental AXI logic up at the top, and the more generic bus logic sprinkled through below.  This turns the logic within the core into something closer to a core on a generic bus.  This example core will also process one axi request per clock, so it's faster and simpler than what you've tried posting above.

That said, let me try to help you out one better than either finding your bug via desk-checking (I'm too tired to see it right now) or offering you an example to compare your code against.  Your problem isn't fundamentally the code you've posted above---even though that's what you've been wracking your brains against.  The problem you are struggling with is more fundamental.  It is your engineering process.  What you need to do first is to build your own AXI master ... not anything full up, but just enough to test your component, something that runs within a simulator.  Then simulate your component.  I wrote about what I'm trying to describe here, and the (verilog) tools I use to do it here.  Further, there's also a description on the zipcpu.com web-site about how to get a trace from within your design on there as well.  (You'll find the AXI scope I linked to you above a cheater's way of bypassing many of the difficulties the web-site works around.)  The reason I point this out is that, it's a whole lot easier to debug a component within a simulation, than within your design.  It's also easier to debug a component within your design if you can get a trace from within it showing you what's going on.

Let me recommend to you that you switch to an easier method of looking for the bug in your code.  :)

Holler if any of that doesn't make sense, or if you still want me to take a hard look through your code on Monday morning.  :D

Dan

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I thank you very much for your reply and for your advice. You are right to said for better manage and control this bus it is necessary to implement its own bus AXI but for reasons of time I can not do it.
I looked at your implementation it looks interesting but it is in Verilog, I have modules implemented in VHDL, so to adapt them it will take me a little time.

I generate it with Vivado it is a simple AXI  lite slave. I'd like you to look at it in more detail. Thank you for your time.

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@sami47,

Ok, so I took a fresh look in the light. You've got a bunch of errors in there.  They are all simple errors.  Further, everything I saw would be revealed by a proper simulation (Consider ghdl and an AXI bus functional model as tools for this).  I'll share with you the errors I saw below, but you need to understand that you are pushing off a problem (not knowing how to simulate this) for later.  You will need to go back and learn how to simulate something like this if you wish to move forward in your digital logic journey.

Enough said.  I'm just trying to look out for you.  ;)  Now on to what I've seen ...

I'm sure you already know by now that an AXI bus has five channels within it.  The indication that a transaction has taken (or literally is taking) place on the bus is that the READY and VALID lines for a particular channel will both be high at the same time.  On *that* clock, the transaction takes place.  It's not when VALID is true and you set READY, but when VALID and READY are both true.

My point is, you cannot check, for example, whether VALID and READY on one channel are true *AND* anything else.  You will lose transactions if you do this.  Look for VALID AND READY.  Any additional logic to this will ... get you in trouble.

As examples, consider your axi_bvalid, axi_bresp, and your axi_rvalid signals.  In particular, your approach to axi_bvalid could lock the bus ... since you'd allow a request to take place that would not get a response.

The next big problem I saw had to deal with timing.  A read needs to take place any time arready and arvalid are true.  If you want to double check that axi_rvalid is false, you'll need to do it before setting arready.  Hence, slv_reg_rden needs a touch of simplification.  Keep in mind, though, from slv_reg_rden, you take two clocks to return a value to the bus, while setting axi_rvalid immediately on the second clock.  Hence the two responses (axi_rvalid and axi_rdata) are not aligned.

Again, a simulation would've revealed all of these problems, and it would've revealed them within about 15 minutes of working with it (once you know how to use it), rather than the days you've struggled with this problem.

Another way you could debug this bus would be to change your axi_rdata output value to be information of the bus transaction taking place, rather than the values you want to get out.  That method may be a touch harder to wrap your brain around (for me too), but I have used it in the past to get information from a system when I am unable to simulate it.

Dan

 

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Tank you for your reply.

I monitor the signals ready and valid that they are both to 1 when i receive data.
But I still can not put a time delay between every 4 bytes I get :(

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@sami47,

You are monitoring signals?  Good.  How many and which signals are you able to monitor?

Dan

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I mean that the signals "ready" and "valid" both of them are at 1 for receiving one 32 bit via slv_reg1 ( i am using the GP0)

the question is how we can put a delay betwen several 32 bits transaction ? thank u

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@sami47,

The following is a pseudo-code description of how to delay the response by one clock.  You could use this approach, if you needed to, in order to delay the response by as many clocks as you would like,

if ((axi_arready)&&(S_AXI_RVALID))
begin
  read_request <= 1'b1;
  read_address <= S_AXI_ADDR;
end else
  read_request <= 1'b0;

case(read_address)
.... // your big case statement
.... // costs you a clock

// Delay the response to rvalid
data_valid <= read_request;
// Here's your actual rvalid response
axi_rvalid <= data_valid;

Dan

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Thanks for your reply, i will adapt it to my code.
I'll keep you informed.

 

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