Shop OBEX P1 Docs P2 Docs Learn Events
How many servos (max) without PSC? — Parallax Forums

How many servos (max) without PSC?

bulkheadbulkhead Posts: 405
edited 2005-10-07 12:22 in General Discussion
Ok, thanks for all the help so far on helping me decide what to get, but I have one last question. If I don't need any I/O pins for input sensors or any other types of output BUT to control servo movement, how many servos could I control by just using the PWM feature of the Javelin stamp alone? I'm about to order the Javelin, but if I can get away with running about 8 servos on just the stamp itself, I'd rather start by doing that than getting the PSC.

Also, after browsing the forums, I've been led to the conclusion that some of these stamps dont have "true" PWM capabilities? Is this not true at all, just true for older models, or does this apply to the Javelin too?

Thanks.

Comments

  • diafysaldiafysal Posts: 92
    edited 2005-10-06 14:31
    There is a limit of 6 virtual peripherals(VP) at once.
    So if you use the PWM VP you can control 6 servos.

    (someone correct me if I'm wrong)
  • bulkheadbulkhead Posts: 405
    edited 2005-10-07 02:57
    Ok, thanks for the info. I realized I really don't need control of 8 servos because two pairs of them do the same thing (I'm using two for the extra power), so I can just wire them to the same I/O pin. Control of 6 should be enough, so I just ordered the stamp itself (I might get the PSC later).

    Now when you say 6 VPs at once, does that mean you can have 6 instances of one type of class (say PWM)? or does that mean you can have 6 types? If it were by instance, then would it be possible to control up to 15 servos (thats the # of I/O pins, right?) with the stamp itself?
  • Peter VerkaikPeter Verkaik Posts: 3,956
    edited 2005-10-07 12:22
    You can have more than 6 VP's but only 6 can be active simultaneously.

    You stated you have 4 pairs of servos, assuming you run these simultaneously,

    you still have 2 vp slots for other VP's. That could be a full duplex bidrectional serial

    channel, or other VP.

    If you dedicate one vp slot to timers (you can have unlimited number of timers,

    as long as ram memory serves, all timers occupy the same vp slot)

    you have one vp slot left that you can use for different VP's at different times.

    (quite possible to have a large number of half duplex bidrectional serial channels,

    provided the javelin initiates serial communication).

    regards peter
Sign In or Register to comment.