03-15-2019 04:02 AM
Hi,
I'm trying to figure out whether I'm using the Digital Waveform Editor V3.0 "fill with value" feature in the correct way.
I have tried with both compare and drive signals, when I enter a value (e.g. 55AA) the highlighted portion of the selected waveform goes high. This doesn't look correct to me. I feel like I'm missing something even though there are a small number of settings to configure with this feature. I cant seem to find any documentation to support this and there is little discussed on NI forums.
Any help would be greatly appreciated.
Thanks,
Sam
Solved! Go to Solution.
03-19-2019 07:55 AM
Hi Sam,
I have never used NI Digital Waveform Editor before, and I couldn't find any specific documentation on the Fill >> Fill With Value feature. So, instead I downloaded the software and experimented a little. This is what I have found:
I started with a blank new waveform (File >> New Waveform...), which has 16 digital signal lines. The signal lines are listed on the left hand side, and the x-axis represent the time and samples.
Next, I selected the areas shown in the image below and used the Fill >> Fill With Value feature. Note that digital means binary, thus any hexadecimal number is interpreted as its binary representation. As an example, I chose 55AA in hexadecimal, whose binary representation is a fifteen digit array of bits: 101010110101010.
(1) 16 signal lines, 1 sample.
I noted that Signal 0 represents the first bit of the number, Signal 1 the second bit, and so on. Since the number 55AA requires only 15 bits, the 16th bit represented by Signal 15 becomes 0.
(2) 9 signal lines, 1 sample.
Now, all selected signal lines became high, i.e. 111111111. This is because the requested value 55AA requires at least 15 bits to be represented. But since only 9 digital signal lines were selected, they all maxed out. The maximum hexadecimal value that can be represented by 9 digital signal lines is 1FF.
(3) 1 signal line, 15 samples.
Again, since the number of selected digital signal lines are fewer than what's required to fully represent the requested number 55AA, all selected digital signal lines were maxed out. In this case, only one digital signal line was selected, hence it became high.
Since 15 samples were selected, the signal remain in its set state for that period.
(4) 16 signal lines, 15 samples.
As a combination of (1) and (3), the number 55AA could be fully represented as 0101010110101010, and was set to a duration of 15 samples.
I hope this provides some clarification.
Best regards,
Marcus
03-19-2019 08:21 AM
Marcus,
Many thanks for taking the time to look into this, it's making a lot more sense now. I was trying to use the feature to write a hex value to only one signal; like you have done in your 2nd example.
Best regards,
Sam