Interfacing custom module with Nios II

It is easier than you think

Instantiate this way:

AES_128_EncryptionCore u0(clk,key,PlainText,Load,reset,CipherText,Done);

You only need to add this glue logic:

wire key[127:0] = { user_dataout_4, user_dataout_3, user_dataout_2, user_dataout_1 };

wire PlainText = user_dataout_0[0];

wire Load = user_dataout_0[1];

wire CipherText

wire Done;

assign user_datain_0[0] = CipherText;

assign user_datain_0[1] = Done;

Here I assumed these register functions:

- the AES key is stored into user_dataout_1 to 4

- user_dataout_0 is a 'control register', where bit 0 is used as data input and bit 1 as load command

- user_datain_0 is a 'status register', where bit 0 is your encrypted data output and bit 1 is the completion signal.

Please note that this is a minimal addresses implementation; these 4 bits can be as well mapped singularly on 4 separated registers.

If you want a smarter code, replace all those user_data_ with the actual register functions, eg control_reg,status_reg,key0,key1,...