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Altera_Forum's avatar
Altera_Forum
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14 years ago

Avalon_ mm_ master wrapper (vhdl)

Hello,

I have written a code for CDMA Encoding and CDMA Decoding using VHDL Language. Now i have to create as a custom IP using component editor.Here i want a help regarding the avalon signals.

In my system , the output from NIOS-II processor will be given to CDMA_Encoding(it encodes 32-bit data from NIOS-II and convert it to 16-bit data) and then given to avalon interface. Similarly from avalon interface i will get 16-bit data,which is given to CDMA decoding( it again converts 16-bit data into 32-bit,as original output from NIOS-II) and then given to slave(like SDRAM or Flash Memory).

NIOS-->CDMA_ENCODING-->AVALON-->CDMA_DECODING-->SLAVE.

this is the flow of system.

Kindly help me regarding creating custom IP to sync with avalon.

i am not able to understand , which signals to be used after reading avalon specification manual.

entity of my custom logic is given below.

CDMA_ENCODING: 

entity CDMA_ENCODING is
	port (rst_n : in  std_logic;
			clk   : in  std_logic;
			PI: IN STD_LOGIC_VECTOR(0 TO 31);
			output :buffer std_logic_vector (0 to 15));
	end CDMA_ENCODING;

CDMA_DECODING: 

                      entity CDMA_DECODING is
						port (
						rst_n : in  std_logic;
						clk   : in  std_logic;
						PI: IN STD_LOGIC_VECTOR(0 TO 15);
						output :buffer std_logic_vector (0 to 31));
					end CDMA_DECODING;

In order to interface with avalon Wrapper is necessary.. kindly give some hints regarding this as soon as possible.

Thank you.

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  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    for reading.... 

    if avs_m0_read='1' then
				avm_m1_read<=avs_m0_read;
				avm_m1_address<=avs_m0_address;
				--avm_m0_waitrequest<='1';
				avs_m0_waitrequest<='1';
								end if;

    for writing.....

    PI_WRAP_EN,PI_WRAP_DE are cdma encoding and decoding port maps.

    here i didnot add byte enable . 

    if avs_m0_write='1' then
			avm_m1_write<=avs_m0_write;
				avm_m1_address<=avs_m0_address;
				avs_m0_waitrequest<=avm_m1_waitrequest;
				avs_m0_waitrequest<='1';
				PI_WRAP_DE<=avs_m0_writedata;
				avm_m1_writedata<=OUTPUT_WRAP_DE;
			end if;

    is that read and write operations are correct.

    Tell me sir,

    Read and write should be '0' or '1' to start operation.

    thank you very much in advance.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    --- Quote Start ---

    for reading.... 

    if avs_m0_read='1' then
                avm_m1_read<=avs_m0_read;
                avm_m1_address<=avs_m0_address;
                --avm_m0_waitrequest<='1';
                avs_m0_waitrequest<='1';
                                end if;

    for writing.....

    PI_WRAP_EN,PI_WRAP_DE are cdma encoding and decoding port maps.

    here i didnot add byte enable . 

    if avs_m0_write='1' then
            avm_m1_write<=avs_m0_write;
                avm_m1_address<=avs_m0_address;
                avs_m0_waitrequest<=avm_m1_waitrequest;
                avs_m0_waitrequest<='1';
                PI_WRAP_DE<=avs_m0_writedata;
                avm_m1_writedata<=OUTPUT_WRAP_DE;
            end if;

    is that read and write operations are correct.

    Tell me sir,

    Read and write should be '0' or '1' to start operation.

    thank you very much in advance.

    --- Quote End ---

    You need to start simulating your design by using a simulator. Some quick comments:

    - The "if avs_m0_read='1' then" (and the same for the write) are not needed. Just look at the code you wrote after the if/then "avm_m1_read<=avs_m0_read" but in order to execute the statement avs_m0_read must already be one which means that "avm_m1_read" will end up being '1' forever once 'avs_m0_read' first gets set to 1.

    - Ask yourself what do you think happens when you hit the statement "avs_m0_waitrequest<='1';". No where will it ever get set back to '0', which means the interface will forever be saying to wait which means it will hang.

    The entire 'if/then' statement needs to be removed.

    Like I said, it's time that you start to run the simulator with your code. Verify that your implementation of the various Avalon signals matches what the specification says.

    Kevin Jennings