The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for June 27th, 2019

Solid State vs. Electromechanical Relays | Arrow.com

Posted by jpluimers on 2019/06/27

For my reading list: [WayBack] Solid State vs. Electromechanical Relays | Arrow.com

When you need a power switching solution, you are faced with two competing technologies – electromechanical relays and solid state relays. So which is the right choice for your design?

Keywords: SSR versus EMR, SPDT

via:

–jeroen

Posted in Development, Hardware, Hardware Development, Power User | Leave a Comment »

The Delphi compiler has a hard time coping with circular unit references

Posted by jpluimers on 2019/06/27

In [WayBack] Anyone here with an “F2092 Program or unit ‘?’ recursively uses itself” error in Tokyo? I have this error in Tokyo but the same project compiles ok in Berlin… – Luis Madaleno – Google+, I commented this:

Large circular reference cycles can trip the compiler into emitting this error (next to out-of-memory errors, access violations and internal errors and “unitX.pas F2063 Could not compile used unit ‘unitY.pas'”).

Solution that usually works: quit Delphi, delete .DCU files, start Delphi, build all, then compile. Cumbersome, time consuming, but since the error is intermittent and involves large code bases, it’s was hard to get it to R&D back in the days.

–jeroen

Posted in Delphi, Development, Software Development | Leave a Comment »

Calculating CRC with a tiny (32 entry) lookup-table | Lentz family blog

Posted by jpluimers on 2019/06/27

For my archive:

I happened to notice that the Arduino OneWire library uses a 256 entry lookup table for its CRC calculations.

I did some research on this topic in 1992-1993, while working on Bulletin Board Systems, FidoNet code and file transfer protocols.

These days memory is not at a premium on most computers, however on Arduino and microcontroller environments it definitely is, and I happen to know that table-lookup CRC can be done using two 16-entry tables!

So I’ve dug up my documentation and code from the time, and applied it to the CRC-8 calculation for the Maxim (Dallas Semiconductor) OneWire bus protocol.

I think this provides a neat trade-off between code size and speed.

License For any of the below code, apply the following license (2-clause “simplified” BSD license), which should suffice for any use. If you do require another license, just ask.

Source: [WayBack/Archive.is] Calculating CRC with a tiny (32 entry) lookup-table | Lentz family blog

The example on the page is for the CRC-8 implementation used in the [WayBack] 1-Wire Communication protocol – Wikipedia.

The generator works for CRC-8, CRC-16 and CRC-32 polynomials and can be downloaded here:

–jeroen

 

Posted in Algorithms, C, Development, Software Development | Leave a Comment »

Supreme / Pearl Drums – Animal | Soundslice

Posted by jpluimers on 2019/06/27

[WayBack] Supreme / Pearl Drums – Animal | Soundslice. Found based on a low-quality video in a private FB channel.

This one is much better (:

–jeroen

Posted in Fun, LifeHacker, Music | Leave a Comment »