LXUSB Signals?

Questions about hardware and software obtained directly from Shoestring Astronomy
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LXUSB Signals?

Post by eplumer » Wed Jul 30, 2008 10:31 am

I am looking into combining my SPC900NC with an LXUSB. I am somewhat confused by all of the the variations on the theme of SC mods. I have looked through the LXUSB manual which has a good summary of cabling on the LXUSB side but is vague on the camera side. I have the following questions:

(1) what is the nature of the 4 signal outputs from LXUSB. Are they TTL 0V/5V, Open collector transistors?

(2) what is the assumed polarity on each of these signals? That is, does LXUSB pull input line down to ground to activate a feature?

My guess, would be that LXUSB pulls shutter low to enable LX, pulls frame transfer lines low on completion of an LX frame to allow frame to transfer, and pulls CCD Amp low to turn off CCD Amp during LX exposure. Do I have these right?

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Re: LXUSB Signals?

Post by dpanderson » Wed Jul 30, 2008 12:00 pm

1) They are open-collector outputs, so they pull down to about 0.2V, and they pull up to whatever voltage is coming from the camera. I believe that is 5V.

2) I believe all signals are active when they are pulled low.

The information found at http://www.pmdo.com/ is really the best source, since Steve Chambers is the true authority on webcam modification.
Doug Anderson
Shoestring Astronomy

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