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Subject: 
Re: Sensor monitoring
Newsgroups: 
lugnet.robotics
Date: 
Thu, 21 Jan 1999 15:50:50 GMT
Original-From: 
Paul Haas <paulh@^StopSpam^hamjudo.com>
Reply-To: 
[paulh@hamjudo]nomorespam[.com]
Viewed: 
1097 times
  
On Wed, 20 Jan 1999, Michael Gasperi wrote:

I think the sensors are read every 3ms and the value stored somewhere.
I don't think they are read just when you ask for them in software.
You get the last value read. I base this on the way the rotation
sensor and some of the sensor modes work. They would require a
separate background task to process.  Two readings would never be at
the exact same time.  I would guess that sensor 1 is always read just
before sensor 2.

The H8 object code reading crowd may know for sure. Those of us with dual
trace oscilliscopes can also figure it out.  An oscilliscope can show when
a port in light sensor mode is being read.  With a dual trace scope we can
see if the sensors are read almost simultaneously, separated by a
millisecond, separated by 100 microseconds or some random interval (not
likely).

I and several other reported months ago that the light sensor is powered
for 3 milliseconds then read for 100 microseconds.  On further reflection,
I suspect it's really powered for 2.9 milliseconds and the whole cycle is
3 milliseconds long.  I must read Kekoa's page, it's probably already
there.

--
paulh@hamjudo.com  http://www.hamjudo.com
The April 97 WebSight magazine describes me as "(presumably) normal".

--
Did you check the web site first?: http://www.crynwr.com/lego-robotics



Message has 1 Reply:
  Re: Sensor monitoring
 
(...) I got around to looking at two inputs at the same time with a dual trace scope. All of the inputs go into the 5V read at the same time! That doesn't say they are read by the uP at the same time, but the switch between power and read and back (...) (25 years ago, 26-Jan-99, to lugnet.robotics)

Message is in Reply To:
  Re: Sensor monitoring
 
(...) I think the sensors are read every 3ms and the value stored somewhere. I don't think they are read just when you ask for them in software. You get the last value read. I base this on the way the rotation sensor and some of the sensor modes (...) (25 years ago, 20-Jan-99, to lugnet.robotics)

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