[HN Gopher] Thunderscope update: My take: Why open source is better
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Thunderscope update: My take: Why open source is better
Author : ChuckMcM
Score : 26 points
Date : 2025-05-01 00:16 UTC (3 days ago)
(HTM) web link (www.crowdsupply.com)
(TXT) w3m dump (www.crowdsupply.com)
| ChuckMcM wrote:
| This is an update from the folks doing Thunderscope (a high
| frequency "soft" oscilloscope) but this really stands out:
|
| _Teaching KiCad a New Trick - Matching Delays
|
| At time of writing, KiCad only understands the length of traces
| and pins. When length matching, it takes length as a single
| number added up across every layer. This leads to delay
| mismatches, as the signals on the inner layers are slower than
| the signals on the outer layers. When assigning pin lengths, you
| need to arbitrarily choose a layer to convert a delay value
| (given by the manufacturer), to a length. This also results in
| delay mismatches._
|
| _I wanted to do this right, just like Altium does, but I didn't
| want to have to calculate and add up all the delay values by hand
| in a spreadsheet. So I made a script to rewrite custom design
| rules to try to get KiCad's length matching to be delay matching
| (including pad delays)._
|
| Closed source design tools leave you stuck, and often when a need
| like this surfaces you end up paying a lot of money for an
| "option pack" that adds the capability. If you have ever wondered
| if KiCad was up to doing _any_ kind of design, this should assure
| you that no it works just fine and you can kick that $10,000
| Altium license to the curb.
| LeonM wrote:
| > Test Rev. 5: This should take no longer than two weeks.
|
| Ah yes, the famous last words of expecting testing to take less
| than two weeks, and that all tests will pass...
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