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very long bit pattern for vbit source

Zitty

Hello,

 I want to test a mixed signal design in cadence virtuoso 6.1.5 with spectre.

To verify the functionallity of the digital part a very long input sequence, thousands of bits, is necessary.

I tried using the vbit source. What is very usefull about this is that it is possible to adjust the voltage levels as well as the length of one bit. This makes it superior over the vpwl  at least for my application.

I found a helpful document that makes it possible to adjust the properties of vbit in a way that it is possible to insert a design variable for the data . Another document helped me to load a bitstream from a tex-file into this design variable inside ade-l. 

The problem is that this is only possible for short bitstreams. At least my bitstream is too long for such a proceeding.

Is there any other approach to solve this problem?

A stimulus file would also be very long/large...

 

regards Zitty 

  •  Dear Andrew,

    I have a file data in column fromat.

    That is, instead of  [ p1 pattern data="10111011011" ], I have in the file ( named clk_bit.txt ) as below:-

    1

    0

    1

    1

    1

    0

    1

    .

    .

    .

    1

    0

     

    Is it possible to source this file in the VSOURCE, without editing the above file.

    If so, could you please tell how it can be done .

    Kind Regards,

  • No -  you'd have to contact customer support and ask for an enhancement request to allow this to be read from a file.

    The alternative might be to use a vector file input - (vec_include) - but even that would need the file in a slightly different format (some additional information at the top).

    Andrew.

  • I had a question asked to me about this post, and it turns out that spectre has been able to read the pattern from a file since at least the time of the post above (I didn't check back to find out when it started working - it might have been always possible). 

    However, the vsource component in analogLib doesn't really support this. CCR 1110227 is there to enable that. Prior to IC617 ISR10 there was a workaround of filling in the filename when the source type was set to "pwl" and then changing the source type to "bit" to fill in the other parameters; unfortunately a change in that ISR causes the parameters to reset after changing the source type. I've filed CCR 1816593 to get that fixed.

    Regards,

    Andrew.

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