Dangerous Prototypes

General Category => General discussion => Topic started by: Sleepwalker3 on January 05, 2015, 02:20:14 pm

Title: Using a hardware or software CRC with enhanced core PIC16F1X
Post by: Sleepwalker3 on January 05, 2015, 02:20:14 pm
The blog post regarding CRC http://http://dangerousprototypes.com/2015/01/03/app-note-using-a-hardware-or-software-crc-with-enhanced-core-pic16f1xxx-in-class-b-applications/ has generated quite a bit of discussion already. The best place for that kind of discussion is here at the forum, so I've started this post for you to all go for your lives on it.
Title: Re: Using a hardware or software CRC with enhanced core PIC1
Post by: neslekkim on January 05, 2015, 03:28:39 pm
Are these new PIC16F161x series available?, I have been searching Farnell for some time now, but only the 1613 is available there.
There are some nice features that would be cool to explore on these.
Title: Re: Using a hardware or software CRC with enhanced core PIC1
Post by: rumburack on January 05, 2015, 03:39:40 pm
To be honest, I have no clue about how to avoid bit flipping ram. That’s why I want to see the discussion, I find the topic is quit interesting, hoping for some smalltalk and insights…. I hoped that someone here had first hand knowledge and could feed me with some web pointers or numbers about how often and where and when and such. :-)

I could think about some ideas how to solve the problem, but due to cluelessness…

* Shield the device. Put some layers of copper/whatever above the ram cells inside the IC? Like those reverse engineering protection stuff?
* Add external shielding? What to use? Create a chip with ECC cells, quite a different design…
* Why use CRC when error correcting software codes exist? (use some memory for a correction map and have a way more useful solution).
* Run two microcontrollers in parallel and sync/compare them somehow?
* If I create something that flies to the moon or carries PAX around, how much cost is acceptable?

All this seems more reliable to me than CRC with still sitting on 0,4% misses.

(Just a copy of my last blog comment.)
Title: Re: Using a hardware or software CRC with enhanced core PIC1
Post by: Sleepwalker3 on January 05, 2015, 04:19:16 pm
[quote author="neslekkim"]Are these new PIC16F161x series available?[/quote]

Digikey has many types, not just the 1613.
http://http://www.digikey.com/product-search/en?x=0&y=0&lang=en&site=us&keywords=PIC16F161

.
Title: Re: Using a hardware or software CRC with enhanced core PIC1
Post by: neslekkim on January 06, 2015, 12:24:39 am
ah, need to yell at farnell then
Mouser is a bit expensive in norway (shipping)
Title: Re: Using a hardware or software CRC with enhanced core PIC1
Post by: Sleepwalker3 on January 06, 2015, 12:28:45 am
That was Digikey not Mouser. Mouser only had the 13, as did RS. Not sure if that is any better, worse or just the same for you.
Title: Re: Using a hardware or software CRC with enhanced core PIC1
Post by: neslekkim on January 06, 2015, 12:31:47 am
[quote author="Sleepwalker3"]That was Digikey not Mouser. Mouser only had the 13, as did RS. Not sure if that is any better, worse or just the same for you.[/quote]

mouser, digikey, samma faen.. :)
same problem :)

I want the ones with the PID stuff..

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