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C/C++ Parallel Port Interfacing

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  • 15-03-2009 11:37pm
    #1
    FrancieB
    Closed Accounts Posts: 42 ✭


    Hi there,

    I am a 2nd year Software Engineering student. This years project involves writing a Modbus communications driver in C/C++ to allow me to talk to a control valve/ level transmitter via the Parallel Port interface on a Comadore 64.

    Has anyone any suggestions on where I might start?


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    #2
    oscarBravo
    Technology & Internet Moderators Posts: 28,804 Mod ✭✭✭✭oscarBravo


    Moved from Open Source - probably get a better response here.


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    #3
    ressem
    Registered Users Posts: 2,426 ✭✭✭ressem


    Well the easy bit...

    Download an c64 emulator that supports the Mos Tek 6526 complex interface adapter chips.

    Download a C compiler with 6526 header files.
    http://www.cc65.org/doc/c64-4.html#ss4.3

    Get the chip datasheet
    http://archive.6502.org/datasheets/mos_6526_cia.pdf

    Get a circuit diagram of how the user port is connected to the 6526.
    http://www.devili.iki.fi/Computers/Commodore/C64/Service_Manual/large/Page_13.gif

    And start by writing a program to change the signal of some of the user port 'pins'.


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    #4
    DublinDilbert
    Registered Users Posts: 5,379 ✭✭✭DublinDilbert


    FrancieB wrote: »
    Hi there,

    I am a 2nd year Software Engineering student. This years project involves writing a Modbus communications driver in C/C++ to allow me to talk to a control valve/ level transmitter via the Parallel Port interface on a Comadore 64.

    Has anyone any suggestions on where I might start?


    What platform are you trying to program on? a PC or comadore 64?? What OS?

    Can you describe the system a bit better and which bits you have to complete as part of this project.... we should be able to point you in the right direction then...


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    #5
    LARDO
    Closed Accounts Posts: 60 ✭✭LARDO


    Do a course that u can get a job paying more than minimum wage when u graduate is my suggestion,lol.


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    #6
    DublinDilbert
    Registered Users Posts: 5,379 ✭✭✭DublinDilbert


    LARDO wrote: »
    Do a course that u can get a job paying more than minimum wage when u graduate is my suggestion,lol.

    That's not very helpful to be honest....

    What course would you suggest doing? Everyone has to start some where...

    There's no course that i know of that you get paid lots of money when you finish.... you always have to serve your time, but as long as your doing something you like, you won't mind....


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    #7
    LARDO
    Closed Accounts Posts: 60 ✭✭LARDO


    Sorry mate ur right,ive worked in this industry along time, a bit cynical by now,on a serious note i suggest u learn a language like german to greatly improve ur job /earning prospects when u graduate. There really is no real money in this business in this country and the quality of work is also appalling in many cases, travel when u graduate, if career progression is what u are interested in.

    Its just that programming is like manufacturing in the early eighties its all going to the third world, u look at a website like elance.com and u c guys doing jobs for 50 dollars and u realize there is no future in it! Im sorry if u dont want to hear this but honestly , i would consider a change of course!

    All this nonsense in the media about a shortage of it grads is for ****ty low paying jobs going nowhere imo. Even if u had a great idea in the morning for a piece of software, after u did the math on the dev. cost u would go to india with it ,what does that tell u about irish programmers job prospects? it Just the way the industry is gone.


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    #8
    DublinDilbert
    Registered Users Posts: 5,379 ✭✭✭DublinDilbert


    I would see being able to travel when you qualify as a major plus, you can get a range of experience....

    I agree there are some problems in the way people are perceived by employers, people become type-cast, this happens in all areas of engineering unfortunately. For example if you do database development for a few years after college, it can be very hard to break out of that and do something different.

    There are many different opportunities within software engineering:-
    Enterprise system development (Database/web services type stuff )
    User interface development
    Automation Systems
    Communication Systems
    Embedded Systems
    Vision Systems


    The only way we are going to get out this current situation is to innovate, this will require lots of different disciplines, software engineering included.


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    #9
    GigaByte
    Closed Accounts Posts: 515 ✭✭✭GigaByte


    LARDO wrote: »
    Sorry mate ur right,ive worked in this industry along time, a bit cynical by now,on a serious note i suggest u learn a language like german to greatly improve ur job /earning prospects when u graduate. There really is no real money in this business in this country and the quality of work is also appalling in many cases, travel when u graduate, if career progression is what u are interested in.

    Its just that programming is like manufacturing in the early eighties its all going to the third world, u look at a website like elance.com and u c guys doing jobs for 50 dollars and u realize there is no future in it! Im sorry if u dont want to hear this but honestly , i would consider a change of course!

    All this nonsense in the media about a shortage of it grads is for ****ty low paying jobs going nowhere imo. Even if u had a great idea in the morning for a piece of software, after u did the math on the dev. cost u would go to india with it ,what does that tell u about irish programmers job prospects? it Just the way the industry is gone.

    With your kind of the glass is half empty attitude I can't imagine you could come up with a good idea for a piece of software even if it bite you on the ass. As for developement costs! lol


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    #10
    stylers
    Registered Users Posts: 184 ✭✭stylers


    don't think any of this software industry talk is going to help the op.. but anyway..

    will you be doing this on actual hardware or is it an airy fairy theoretical type assignment ?. Can't think why a parallel port was chosen for this as modbus is essentially a serial protocol, so you're effectively going to be bit-banging.. but as ressem says (assuming you don't have an actual C64 to play with) you need to start hunting for an emulator. then some details of the C64 rom functions might help.. then datasheets.. then the MODBUS protocol.. addressing details of the control valve and level transmitter etc.. there's quite a bit to figure out there if you actually need to make this work..


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    #11
    LARDO
    Closed Accounts Posts: 60 ✭✭LARDO


    GigaByte wrote: »
    With your kind of the glass is half empty attitude I can't imagine you could come up with a good idea for a piece of software even if it bite you on the ass. As for developement costs! lol

    i dont think u read my post correctly giga, i dont think the glass is half full , i think its empty mate,lol. If u want to elaborate on dev. costs i would be delighted to discuss it with u, but ur 4 word sentence on the matter doesnt explain very much! U are just another of theses snide posters who insult without any explanation, a little girl so to speak running to mummy,lol.


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