Re: [oc] micro sequencer

["Jim Dempsey" <dempsey@northnet.net>]

----- Original Message -----
From: "Jamil Khatib" <khatib@ieee.org>
To: <cores@opencores.org>
Cc: <bluetooth@opencores.org>
Sent: Sunday, December 30, 2001 3:51 PM
Subject: [oc] micro sequencer


> I am trying to implement it using a counter and a ROM but according to
> the above details the ROM has to be very large and very wide and filling
> its contents is very hard. Other CPUs consumes lot of resources.
> Do you have any suggestion how this can be done?

Examine your signal requirements for independance of operation.
Find groupings of signals were only one of the signals is asserted at
any on time. If, for example, you find 5 to 8 such signals then you
can encode the signal into 3 bits (width) of your ROM. Then add a
3 to 8 decoder to your circuitry. Likewise you can use a 2 to 4,
4 to 16, 5 to 32, ... decoders. Depending on the circumstances you
narrow your ROM width significantly

Another technique is to use one or more of the address lines in
your selection.
e.g. if xxx is asserted when address(6)==0 then yyy else zzz

Another technique is to multiplex the signals. i.e. if group A is x
then decode group B using a set of rules enabled when group A is x.
This is similar to the first technique. However, note that if your ROM code
has a "Next Address" field then when not performing a Jump to "Next Address"
that these bits can be used for signal generation.

Jim Dempsey




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