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problematic system call for VHS transport function

Seems that the rewind/review command while vhs is playing so user can scan backward and view also is acting up( or may have always done this). Forward scan is fine ( tp 43). tp 44 however does not scan backwards. You can however push stop and then it will rewind after pushing button number 44. the user cannot however view the process. here is the code:

IF(VHS1_SELECT)
{
SYSTEM_CALL'VCR1'(VHS1,TP,40,41,42,43,44,45,0,0,0)
PUSH[TP,40]
{
ON[FLAG]
}
PUSH[TP,41]
{
OFF[FLAG]
}
IF(FLAG)
{
RELEASE[TP,44]
RELEASE[TP,43]
{
SYSTEM_CALL 'FUNCTION'(VHS1,PLAY,0)
}
}
}
Should I just eliminate the system call and do a push to or something similar? Thanks for your time.
this code was written almost 10 years ago for Access and may have never worked completely.
Any ideas from you kind people?
Stewart lane
Media tech 2
Middlebury college

Comments

  • Stephen BoltonStephen Bolton Junior Member Posts: 345
    Stewart wrote: »
    Seems that the rewind/review command while vhs is playing so user can scan backward and view also is acting up( or may have always done this). Forward scan is fine ( tp 43). tp 44 however does not scan backwards. You can however push stop and then it will rewind after pushing button number 44. the user cannot however view the process. here is the code:

    IF(VHS1_SELECT)
    {
    SYSTEM_CALL'VCR1'(VHS1,TP,40,41,42,43,44,45,0,0,0)
    PUSH[TP,40]
    {
    ON[FLAG]
    }
    PUSH[TP,41]
    {
    OFF[FLAG]
    }
    IF(FLAG)
    {
    RELEASE[TP,44]
    RELEASE[TP,43]
    {
    SYSTEM_CALL 'FUNCTION'(VHS1,PLAY,0)
    }
    }
    }
    Should I just eliminate the system call and do a push to or something similar? Thanks for your time.
    this code was written almost 10 years ago for Access and may have never worked completely.
    Any ideas from you kind people?
    Stewart lane
    Media tech 2
    Middlebury college
    Personally I'd get rid of the system_call. You have a very simple transport arrangement here that needs very little code.

    Depending on the VCR, you could program the FWD and REV buttons as TO's, not PULSE's and you can achieve your push/search functionality. Some VCRs need a longer push to instigate search, and this method would cover that too.

    You might code yourself a play flag so that you can monitor and correctly issue a pause command. Also, then, you can issue momentary feedback to your search buttons showing search or latched on feedback for high speed transport (assuming the VCR is stopped).

    HTH
  • StewartStewart Junior Member Posts: 37
    system call vcr transport

    Thanks Steve. Something along these lines?
    }
    PUSH[TP,40]
    {
    TO[VHS1,1]
    }
    PUSH[TP,41]
    {
    TO[VHS1,2]
    }
    PUSH[TP,42]
    {
    TO[VHS1,3]
    }
    PUSH[TP,43]
    {
    TO[VHS1,4]
    }
    PUSH[TP,44]
    {
    TO[VHS1,5]
    }

    The flag would keep an eye on the vcr being in "play" mode? as before
  • patbpatb Junior Member Posts: 140
    You have to understand the nature of the VCR system calls and how they work. There is a reason there are 10 or more VCR system calls - different decks operate in different fashions and the system calls were made to give the end user the same performance no matter what deck was used. Some handle searches differently, some handle play/pause differently. You never mentioned the make/model of the VCR you are using - which is of paramount importance when determining which system call to use. I suspect that the VCR system call did indeed work fine when it was installed, but at some point in time a new VCR was installed (is that true?) which operates differently and even though the IR file may have been updated, the system call was not updated to match.

    I will have to search through my notes, but I seem to recall that Panasonic VCRs used VCR3 system calls, other calls were written for other models and how they operate. Back in the days when VCRs were still heavily in use I had all of the calls memorized for which one was used with what deck, but I haven't written a job with a stand-alone VCR in quite a while. Don't give up on the system call - instead do the research and find out which system call should be used for the particular make/model that you have.

    I question the logic of putting a play function call on the release of the ffwd/rewind buttons. If the proper system call is used there is no need for that piece of code or the code tracking the "flag" variable.
  • StewartStewart Junior Member Posts: 37
    vcr system call problems

    Indeed it is a replacement vcr
    Sony ( as was the previous one but that was 9 yrs old SONY SLV-ED7FS unit)
    This is a SONY SLV-ED939
    Any idea where I might research the system call for this particular units. Thanks for your time
  • patbpatb Junior Member Posts: 140
    I can't remember where my reference is to match the system calls with the VCRs - I do remember that VCR3 was for Panasonic and that VCR1, VCR2 and VCR4 were the most common.

    Take out the code associated with the release statements and the code keeping track of a flag - you don't need that. Then experiment between using VCR1, VCR2 and VCR4 and see which works best. That would probably take less time then trying to find the references that tell you which one to use.
  • StewartStewart Junior Member Posts: 37
    VCR system calls continued

    By going to access help topics i took a look at all of the vcr system calls

    i rewrote code ( simply changing numbers 1 to 2 etc) and tried vcr2,vcr3,vcr4,vcr5 vcr9. the others seemed to be written for U -matic or panasonic devices. The functionality was there for everything but now a "forward scan option". the VCR1 system call would not work this new vcr to rew-scan. now the other VCR(2-5) system call allows rew-scan but upon forward scan goes directly to a blue screen and indeed scans forward.and upon a release of button it goes into play. So it appears that I can do either forward search or rewind search but not both with any of the system calls with this newer Sony vcr . Any ideas where I might research this?
  • patbpatb Junior Member Posts: 140
    You never said if your code has 5 or 7 buttons? Do you have separate search fwd and search rev buttons (4 buttons) or do you have just 2 buttons that share functions? if Using 5 buttons (play, stop, pause, ffwd, rewind) does not give you the functions you want, try the same system call with 7 buttons (play, stop, pause, ffwd, rew, search fwd, search rev).
  • StewartStewart Junior Member Posts: 37
    VCR system calls continued

    There are 5 buttons . Play/pause /stop and search forward and search reverse

    There seems to be functionality one way but not the other. By pushing search forward the image is projected and it scans forward. On reverse scan however the image goes to blue and by pushing button agan it goes into a rewind with double arrows and projects a blue screen. I used a different system call and the reverse was true One or the other ( forward or reverse) works normally and you can view the image as it goes in 1 direction but not both . Should i simply eliminate the system call entirely? I have tried all I have on file.
    Thanks again!!!
  • DHawthorneDHawthorne Old Timer Posts: 4,584
    I've never once used a system call. For one, I don't like fake feedback, so for one-way IR devices, I make my buttons all momentary. It saves a lot of annoyance calls from the customer that claimed their stop button was lit, but neglected to say they hit play on the front panel when they loaded the tape. Second, scan, slow, and fast modes are the only things that differ from model to model, and it's easy enough to toss a line or two of code in there to compensate; everything else is a direct map (play button pulses play IR channel, etc.). More often than not, the biggest difference is whether you need to hold the buttons down for fast scans or just pulse them.
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