Help! Bus notation on schematics

Hi,

Using the Cadence schematic tool, I have a cell instantiated 128 times,
Icell1<127:0>.

I want groups of 4 cells at the time to have the same input, so there will
be 32 signals, x<31:0> going to 128 cells.

I can label the bus to the input

etc., x<1>, x<1>, x<1>, x<1>, x<0>, x<0>, x<0>, x<0>

but it is a very long string.

What is the syntax to abbreviate it, such as

etc., ((x<1>) *4), ((x<0>) *4)

or something even shorter such as

bit=0; (((x<bit + 1>) *4) *32)



Thanks,

Joe
joe.clark@

 

Virtuoso Schematic Editor User Guide,
Section: Multiple-Bit Wire Connections
Section: Wire-to-Iterated Instance Connections
Section: Multiple-Bit Wire Naming Conventions


Bernd

 

All:

I defy anyone at Cadence to tell me exactly how bus ripping works.
The documents below describe a subset legal bus definitions that work, but
other esoteric combinations work.
The custom memory group at my ex-employer used some pretty wild combinations
that worked.
As a matter of fact, they would write bus def's just like you describe them
( something like <4*i<31:0>> and they would get the bus you describe .. )
I will ask former member of the group for the syntax he uses and post it!

-- Gerry

 

Oh, it's really not as complicated as all that! Starting with the one
that is wanted, here's a variety of examples of varying complexity (the
examples are followed with an representation of the sequence they
expand to).

Put simply - 0:n*m repeats each bit m times, whereas (0:n)*m repeats
the whole 0:n range m times one after the other. Then you can concatenate
them too, and further group them with parentheses, and so on.

x<0:31*4>

0,0,0,0,1,1,1,1,2,2,2,2....,31,31,31,31

x<(0:31)*4>

0,1,2,3,4,5,6,...31,0,1,2,3,4,5,6,...31,...

x<(0:31*2)*2>

0,0,1,1,2,2,3,3,...,31,31,0,0,1,1,2,2,3,3,...,31,31

x<0:31*2,31:0*2>

0,0,1,1,2,2,3,3,...,31,31,31,31,30,30,29,29,...,2,2,1,1,0,0

x<(0:31,31:0)*2>

0,1,2,3,4,...,31,31,30,29,...,2,1,0,0,1,2,3,4,...,31,31,30,29,...,2,1,0

Regards,

Andrew.

 

Yes it can be easy, but you can nest them in complex ways and they still
work.
(negative counting works too in x<31:0> arrays or more complex like
y<31:0:-2> (i think!) )

by the way ... don't you mean

x<0:31>*4

expands to

x<0>,x<0>,x<0>,x<0>,x<1>,x<1>, ... ,x<31>,x<31>

etc.

-- Gerry

 

Thanks for the answers and ideas, guys.

Joe

 

Hi,

Maybe someone could clarify one more question in this thread, please.
Is there is any possibility to deal with two-dimensional arrays of
instances and wires?
I have a 2D array of cells, and so far I could not find a way to
instantiated it, rather than
creating an additional component X- which is 1D array, and than creating
an array of X's.

And correspondingly is there a way to index wire in a 2D manner.

Thank you.
Alex

 

Hi,

Maybe someone could clarify one more question in this thread, please.
Is there is any possibility to deal with two-dimensional arrays of
instances and wires?
I have a 2D array of cells, and so far I could not find a way to
instantiated it, rather than
creating an additional component X- which is 1D array, and than creating
an array of X's.

And correspondingly is there a way to index wire in a 2D manner.

Thank you.
Alex


Virtuoso Schematic Editor User Guide,
Section: Multiple-Bit Wire Connections
Section: Wire-to-Iterated Instance Connections
Section: Multiple-Bit Wire Naming Conventions


Bernd

JC wrote:
Hi,
Using the Cadence schematic tool, I have a cell instantiated 128 times,
Icell1<127:0>.
I want groups of 4 cells at the time to have the same input, so there
will be 32 signals, x<31:0> going to 128 cells.
I can label the bus to the input
etc., x<1>, x<1>, x<1>, x<1>, x<0>, x<0>, x<0>, x<0>
but it is a very long string.
What is the syntax to abbreviate it, such as
etc., ((x<1>) *4), ((x<0>) *4)
or something even shorter such as
bit=0; (((x<bit + 1>) *4) *32)
Thanks,
Joe
joe.clark@