Subject:
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Re: 6 servos
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 22 May 1996 15:42:57 GMT
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Original-From:
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Fred G. Martin <fredm@media.mit%stopspam%.edu>
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Viewed:
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1035 times
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> > The boards take serial input (2400 or 9600 baud). It is
> > straightforward to write a 6811 assembly routine to output such serial
> > signals on an arbitrary digital output.
> Are the digital outputs at 5v high? I think you mentioned on the HB
> homepage about the serial interface converting RS232 levels at +12 and
> -12v to TTL level s (5v). I'm not that familiar with the nitty gritty
> of RS232 so this kinda puzz les me.
There are two types of serial voltages: TTL level and RS-232 level.
The HB's serial interface board converts from TTL to RS-232 for
communicating with the host computer.
The Scott Edwards board accepts TTL levels, so an HB pin can drive it
directly.
The translation between logical level (e.g., is the bit a 1 or a 0),
TTL, and RS-232 is anything but obvious:
logical level TTL level RS-232 level
zero or idle +5v -12v
one 0v +12v
Hope this helps.
-Fred
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Message has 2 Replies:
 | | Re: 6 servos
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| (...) Just to make sure it wasn't a typo...so, the TTL level is "ative low"? Also. Does the Scott Edwards board have the ability to be connected to a computer? or do you need a "TTL to RS232 converter"? (28 years ago, 22-May-96, to lugnet.robotics.handyboard)
| | | Re: 6 servos and RS232...
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| (...) From memory of my designer engineer days, the EIA RS232 specification quotes something along the lines of: logical level RS-232 level zero or idle -3V to +15V one +3V to -15V The spec gave maximum slew rates for signals and such specifics such (...) (28 years ago, 22-May-96, to lugnet.robotics.handyboard)
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Message is in Reply To:
| | Re: 6 servos
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| (...) Are the digital outputs at 5v high? I think you mentioned on the HB homepage about the serial interface converting RS232 levels at +12 and -12v to TTL levels (5v). I'm not that familiar with the nitty gritty of RS232 so this kinda puzzles me. (...) (28 years ago, 22-May-96, to lugnet.robotics.handyboard)
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