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 Robotics / RCX / 2210 (-20)
  Re: Low level programming of the RCX
 
(...) If you're really really hard core you could code in machine code (hex :^) Kevin (21 years ago, 12-Sep-03, to lugnet.robotics.rcx, FTX)
 
  Re: Low level programming of the RCX
 
(...) If you're really hard-core, you could program it in assembly language. I believe the official SDK lists all the operations. Get it (URL) here> if you don't already have it. (21 years ago, 12-Sep-03, to lugnet.robotics.rcx, FTX)
 
  Re: Low level programming of the RCX
 
(...) Speaking of Quite C, I am working on figuring out a good way to integrate Quite C into the BricxCC system. It is a bit different from the other languages BricxCC supports in that you compile to an SREC and download it as a new firmware rather (...) (21 years ago, 12-Sep-03, to lugnet.robotics.rcx)
 
  Re: Low level programming of the RCX
 
(...) [snip] (...) [snip] I'll second that. The BrickOS source code provides a good example of using the FRC as well as other low-level I/O. Between that source and the H8 manuals, you should be set. If you have specific questions, there are quite a (...) (21 years ago, 12-Sep-03, to lugnet.robotics.rcx)
 
  Re: Low level programming of the RCX
 
(...) Quite C is your best place to start with a language. C can give you direct access to the timer. The timer is considered an I/O device, but all I/O on the H8 is memory mapped. Having said that, if you know the address of the timer, you can (...) (21 years ago, 12-Sep-03, to lugnet.robotics.rcx)
 
  Low level programming of the RCX
 
Hello everybody, I try to program the RCX at low level. I want to be able to program using the Hitachi h8/3292 directly. For example, I want to use the free-running timer, define own interrupt handlers and so on. In fact, I *really* need to control (...) (21 years ago, 12-Sep-03, to lugnet.robotics.rcx)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
(...) I've made one. A wall follower. I set the sensor to raw mode and looked at three ranges. It tried to stay in the middle range, which for this 'bot meant lightly touching the wall. The wall follower had a bumper analogous to a highly curved (...) (21 years ago, 12-Sep-03, to lugnet.robotics.rcx)
 
  Touch Sensor resistance versus button displacement
 
Here is a chart showing the variation of contact resistance of several touch sensors while pressing button very progressively. (URL) There are huge differences between various sensor Lightly pressed touch sensors have contact resistance in the 2 to (...) (21 years ago, 11-Sep-03, to lugnet.robotics.rcx, FTX)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
"Steve Hassenplug" <Hassenplug@mail.com> wrote: [snip] (...) This has always annoyed me about the Lego touch sensors. Has anyone ever made or seen a contraption that uses the variable pressure sensitivity of the Lego touch sensors? Tim (21 years ago, 11-Sep-03, to lugnet.robotics.rcx)
 
  USB tower fast firmware download
 
Thanks to Dick Swan's help I have managed to get BricxCC downloading firmware in fast mode with the USB tower. All it took was using long enough timeout values (I'm currently using the tower default timeout settings when downloading firmware), (...) (21 years ago, 11-Sep-03, to lugnet.robotics.rcx)
 
  Re: leJOS & BricxCC news
 
(...) Yes, it would be nice, plus the two or three unused sensors... I'm happy enough with the LDCC firmware as a DCC encoder (pleased as punch, really). But it "would be nice" if it were implemented as a library or patch to an existing brick OS (...) (21 years ago, 11-Sep-03, to lugnet.robotics.rcx, lugnet.trains, lugnet.robotics.rcx.pbforth, lugnet.org.us.indylug)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
(...) I have tried this method too, and as you say in your text, it is plagued by the rubber contacts whose value goes down as more pressure is applied to the switch. I measured resistance of several touch sensors while applying a very progressive (...) (21 years ago, 11-Sep-03, to lugnet.robotics.rcx)
 
  RE: Multiplexing 4 touch sensors on an RCX input port
 
(...) Ian, Great to see that you are having success with pbForth! I have a couple of questoins: 1. Which version are you using? 2. Are there any features you REALLY wish were available? 3. Do you have any stories or code to share? Ralph ---...--- (...) (21 years ago, 10-Sep-03, to lugnet.robotics.rcx, lugnet.robotics.rcx.pbforth)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
(...) It works very well for me, with the variation that I use home-made touch sensors that are actually microswitches embedded into 2x2 blocks. That does mean you might need to debounce in software, but normally I don't bother since the inertia of (...) (21 years ago, 10-Sep-03, to lugnet.robotics.rcx)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
I have done work in this area. I chose to solve the problem to permit 4 touch sensors to be pressed in any arbitrary combination with high probability of getting the answer right :) A simple R, 2R, 4R, 8R scheme will do. I chose R = 40.2K. This is (...) (21 years ago, 10-Sep-03, to lugnet.robotics.rcx)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
(...) Good analysis. Series can work quite well as long as you know that the touch sensors are touched mutually exclusively, but you are right parallel doesn't work well. I remember trying to come up with good resistance values to do parallel, and (...) (21 years ago, 9-Sep-03, to lugnet.robotics.rcx)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
(...) While in theory, this sounds very cool, in pratice, I doubt it will work quite that well. The biggest problem will be that the standard touch sensors may not be 100% on when you press it. This means the sensor itself can provide some (...) (21 years ago, 9-Sep-03, to lugnet.robotics.rcx)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
(...) I don't think that would work very well, as the lights have a rather low resistance, lower than a pressed touch sensor ((URL) as a purist you can use the cybermaster sensors to multiplex three inputs ((URL) Jürgen Stuber <stuber@loria.fr> (...) (21 years ago, 9-Sep-03, to lugnet.robotics.rcx)
 
  Re: Multiplexing 4 touch sensors on an RCX input port
 
(...) LEGO purists use LEGO light bricks as resistors. I created potentiometer bricks, where the resistance is variable for each brick. Two stacks of 4 potentiometer bricks can be seen to the left of the RCX. In this case each stack puts the (...) (21 years ago, 9-Sep-03, to lugnet.robotics.rcx)
 
  Multiplexing 4 touch sensors on an RCX input port
 
You can use four touch sensors per input port on the RCX. The Cybermaster touch sensors have resistors in parallel, and this is how the Cybermaster knows which implement is attached to the tracked robot. It uses its sensor input as a temperature (...) (21 years ago, 5-Sep-03, to lugnet.robotics.rcx)


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