8 bit shift register

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Posts: 17
Joined: October 21st, 2013, 5:11 pm

8 bit shift register

Post by yabapolido » November 4th, 2013, 7:26 pm

I need some enlightment please.
I've been reading about serial to parallel shift registers. But I'm having some trouble from theory to practice.
In the Hello World example, how would one do an echo back after pressing enter?
Given then rx_data is 8bits, I would store this in ram? and then when enter is pressed it would read it back to tx_data.
I can't figure out how to "glue" this... rx_data - serial to parallel - ram - parallel to serial - tx_data

(The point of this (after understanding the basics) is using an already made MD5 core, I would input the string and after pressing enter, it would read back the hash)

Thanks in advance!

Posts: 46
Joined: March 1st, 2014, 2:37 pm

Re: 8 bit shift register

Post by otzen42 » March 1st, 2014, 3:06 pm

You might consider a FIFO. You should be able to generate one using ISE Coregen.

My person plan of attack would be to use an FSM which would read the incoming byte (with the example serial_rx), if it isn't enter (CR or NL, whichever you are using) then write it to the FIFO. If you do get an enter, then enter a loop which reads the contents of the FIFO out and sends them back through the example serial_tx block. You could then replace the FIFO with your MD5 algorithm once you have it working.

Hope this helps.

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