Perl and Can Bus

Jalcock501 has asked for the wisdom of the Perl Monks concerning the following question:

Hi Guys

I am trying to write a script that reads in a constant stream of HEX lines and writes them out to screen in a (sort of) ascii table

 
         _______________________
0CFFE000|00|00|00|00|00|00|00|00|
         -----------------------
18FEF501|00|00|00|00|00|00|00|00|
         -----------------------
IDENTIER|  8 sets of HEX bits   |
         -----------------------
[download]

As it is streaming data I need to keep the identifier static and just update the bits as they come in. The data comes through like this:

12345678:123 0CFFE000 00 00 00 00 00 00 00 00
87654321:321 18FEF501 00 FF 32 C4 FF 00 00 00
43215678:132 0C11FF00 FF FF FF FF FF FF FF FF
12348765:312 18FFE100 23 E0 C1 0E FF 00 AC 00
43218765:112 00000000 01 FF FF FF FF FF FF FF
12345678:123 0CFFE000 01 00 00 00 00 00 00 00
87654321:321 18FEF501 00 00 00 00 00 00 00 00
43215678:132 0C11FF00 00 00 00 00 00 00 00 00
12348765:312 18FFE100 00 00 00 00 00 00 00 00
43218765:112 00000000 00 00 00 00 00 00 00 00
12345678:123 0CFFE000 00 00 00 00 00 00 00 00
[download]

Unfortuantely I have no idea how to handle constant data input. Would someone mind helping as I cannot find examples online either

Thanks

Jim

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Re: Perl and Can Bus by Corion (Patriarch) on Dec 12, 2014 at 14:48 UTC
If you want to output the bytes received for `0CFFE000` and `18FEF501` onto a fixed screen position, the following could help. It's a very simplicistic approach: `open my $can_bus, "./receivetest \|" or die "Couldn't read from CAN bus: $!"; my %last_value; while( <$can_bus>) { if( /^(........:...) (........) (.*)$/ ) my( $something, $id, $payload)= ($1,$2,$3); $last_value{ $id }= $payload; system('clear'); # clear screen # print the table for my $id (sort keys %last_value) { print "$id\t$last_value{ $id }\n"; }; } else { warn "Ignoring unknown line:"; warn $_; }; };` [download] If you want something fancier than the flickering screen, you'll have to look at Curses (or NCurses).	[reply] [d/l] [select]
Re^2: Perl and Can Bus by Jalcock501 (Sexton) on Dec 12, 2014 at 16:25 UTC
Hi Carion Thanks you have really helped I also need to count the amont of times an $id has been read and the elapse time between the messages, I'm not sure how to count entries in a hash, and I am trying to use the Time::Elapse module but if I do`Time::Elapse->lapse($last_value{$id} = $payload);` I get this output `0C11FF00 00:00:00.002815 [00:00:00.000049 [00 00 00 00 00 00 00 00]] but I only want 0C11FF00 00:00:00.000049 [ 00 00 00 00 00 00 00 00]` [download] If I try to but the Time::Elapse anywhere else it errors or am I missing some control character to wrap around the $id	[reply] [d/l] [select]
Re^3: Perl and Can Bus by Corion (Patriarch) on Dec 12, 2014 at 18:43 UTC
You will have to show some code that reproduces the problem.	[reply]
Re^4: Perl and Can Bus by Jalcock501 (Sexton) on Dec 15, 2014 at 09:42 UTC
Re^5: Perl and Can Bus by Corion (Patriarch) on Dec 15, 2014 at 10:01 UTC
Re: Perl and Can Bus by BrowserUk (Patriarch) on Dec 12, 2014 at 14:12 UTC
Unfortuantely I have no idea how to handle constant data input. What is the source of the data stream? With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply]
Re^2: Perl and Can Bus by Jalcock501 (Sexton) on Dec 12, 2014 at 14:15 UTC
./receivetest a pcan linux driver script	[reply]
Re^3: Perl and Can Bus by BrowserUk (Patriarch) on Dec 12, 2014 at 14:18 UTC
./receivetest a pcan linux driver script So that's an executable you have to run and it writes the data stream to stdout? With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply]
Re^4: Perl and Can Bus by Jalcock501 (Sexton) on Dec 12, 2014 at 14:20 UTC
Re^5: Perl and Can Bus by BrowserUk (Patriarch) on Dec 12, 2014 at 14:26 UTC
Re: Perl and Can Bus by karlgoethebier (Abbot) on Dec 12, 2014 at 14:22 UTC
You mean CAN bus? Regards, Karl ŤThe Crux of the Biscuit is the Apostropheť	[reply]
Re^2: Perl and Can Bus by Jalcock501 (Sexton) on Dec 12, 2014 at 14:41 UTC
Yes CAN bus, the script to to take the output of the received CAN signals and write a report to screen that doesn't just stream down the page	[reply]
Re^3: Perl and Can Bus by karlgoethebier (Abbot) on Dec 12, 2014 at 15:33 UTC
Thank you Jalcock501. I didn't know about Can bus until today. Update: Fixed some typos. Regards, Karl ŤThe Crux of the Biscuit is the Apostropheť	[reply]
Re^4: Perl and Can Bus by Jalcock501 (Sexton) on Dec 12, 2014 at 15:43 UTC