Converting VCD digital signal to Analog signal - Analog "X" voltage field always evaluates to (vhi+vlo)/2 - Error

Dear abiquid,

aviquid said:

However, the tool ignores the "X" value and always outputs 0.5 as value for X. I tried using vhi, vlo, as values for "X", and I get the same result as 0.5 (shown in image below, first is the digital vcd, second is the analog converted signal).

Did you try entering your desired value of 0 as the default value for ViVA in your .cdsenv file?

viva.trace dToAHiVoltage string "1.0"

viva.trace dToALoVoltage string "0.0"

viva.trace dToAXVoltage string "0.0"

I believe you will need to restart Virtuoso to see any change it effects.

Shawn

This is nothing to do with a .cdsenv setting. There just seems to be a bug - the "X" setting - either on the Digital to Analog form, or using the awvDigital2Analog function, simply does not work. The documentation describes that it can be a number, or vprev, or some function of vhi/vlo, but it always seems to use (vhi+vlo)/2 regardless of what is passed. I assume this broke at some point, but it's certainly broken in IC6.1.8 ISR34.

I couldn't find a report of this, so I filed CCR 2893484 to address this. You might want to contact customer support and request a duplicate is filed on your behalf so that you can track this.

Regards,

Andrew

Dear Andrew,

Andrew Beckett said:

This is nothing to do with a .cdsenv setting. There just seems to be a bug - the "X" setting - either on the Digital to Analog form, or using the awvDigital2Analog function, simply does not work.

Thank you! Naturally, I was unable to verify that there was a bug...so I appreciate you filling us in!

Shawn

ShawnLogan said:

Thank you! Naturally, I was unable to verify that there was a bug...so I appreciate you filling us in!

Of course, but maybe speculation on something like this is of limited value... there's a reason why I typically quickly test things before answering to ensure that the behaviour is indeed as I'd expect.

Andrew