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Conference hydra::amiga_v1

Title:AMIGA NOTES
Notice:Join us in the *NEW* conference - HYDRA::AMIGA_V2
Moderator:HYDRA::MOORE
Created:Sat Apr 26 1986
Last Modified:Wed Feb 05 1992
Last Successful Update:Fri Jun 06 1997
Number of topics:5378
Total number of notes:38326

291.0. "2nd mouse port?" by ECC::JAERVINEN (impersonal name) Mon Feb 02 1987 09:53

    Are the pins on the second mouse port (or on the first for
    that matter) strictly input or can the be (mis)used for output too
    (bidirectional a la C-64)?
    
T.RTitleUserPersonal
Name
DateLines
291.1only 2 bits out per portBAGELS::BRANNONDave BrannonWed Feb 04 1987 23:4115
    yes, they are bidirectional.  According the Hardware RKM, "the
    pot-control register controls a four-bit bidirectional i/o port
    that shares the same four pins as the four pot inputs.  Instead
    of using the pot pins a variable-resistive inputs, you can use
    these pins as a four-bit input/output port."  That pins 9 and 5
    of each port.
    
    It also says that there are large capacitors on these lines, and
    it can take up to 300 microseconds for the line to change state.
    
    I didn't find anything that said the joystick lines could be
    used for output.  

    -dave    
    
291.2ECC::JAERVINENimpersonal nameThu Feb 05 1987 03:363
    Thanks.... one of these days, after recovering from the financial
    shock caused by bying the machine itself (bought it last night)
    I'll get all these manuals...
291.3BAGELS::BRANNONDave BrannonThu Feb 05 1987 13:1313
    Documentation is one of those hidden costs you find out about usually
    after buying the computer.  I bought the Rom Kernal manuals one
    at time, each time thinking i didn't need the lower level ones.
    Its a nice reference, but not absolutely essential for programming.
    But curiousity about what was in the manuals i didn't buy really
    got to me after about 2 months.
    
    I'm currently working thru a book called Inside the Amiga, which
    gives a good C programming overview of the entire system.  I use
    the RKMs for detailed info on particular sections.
    
    -dave
    
291.4ECC::JAERVINENimpersonal nameFri Feb 06 1987 04:175
    Yes... I knew about those costs *before* buying my Amiga, but I'm
    just cheating myself and buying them a bit later... besides, for
    the time being, I have enough to do learning the more basic features
    of my new toy..