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PSriv8's avatar
PSriv8
Icon for New Contributor rankNew Contributor
5 years ago

Do ROM and/or Lookup Tables introduce an additional delay to the overall circuit?

I want to design a circuit in which a 5-bit input In[4:0] (ranges from 0 to 31) is associated with a corresponding 3-bit output Out[2:0]. I can design this using a 8x3 Encoder in which 5 out of 8 inp...
KhaiChein_Y_Intel's avatar
KhaiChein_Y_Intel
Icon for Regular Contributor rankRegular Contributor
5 years ago

Hi,

I am sorry for the confusion. I meant adding a register to the output of the data -- synchronous. For Asynchronous and synchrnous circuit, both use the LUT. For combinational functions, the registers are bypassed and the output of the look-up table (LUT) drives directly to the outputs of an ALM. The ALM can drive out registered and unregistered versions of the LUT or adder output depending on your design.

Thanks.

Best regards,

KhaiY

  • PSriv8's avatar
    PSriv8
    Icon for New Contributor rankNew Contributor
    5 years ago

    Hi,

    Thank you for your reply.

    I am using an asynchronous design which needs a Request signal to start a process and Acknowledge Signal is sent once the process is complete, unlike synchronous circuits where clock signal(s) exists to coordinate their activities.

    Now if I store the 3-bit data in LUT, where LUT is used as memory.. and I send a Request signal to start the process, would it take additional time to access the data from memory? As I mentioned before, I can also use an 8x3 encoder in place of memory to provide the 3-bit output. Do the memory and encoder both take the same amount of time to process the data once the Request signal is available ?