Subject:
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Re: Transmitting time USB vs serial
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Newsgroups:
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lugnet.robotics.rcx.java
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Date:
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Sun, 5 Jan 2003 23:02:42 GMT
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Viewed:
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5047 times
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In lugnet.robotics.rcx.java, Michael Heinrich writes:
> I measured the transmitting time of an Int from PC to RCX with the
> attached programs and got the following result:
>
> 1. single integer (LED at the tower is off before pressing ENTER):
> USB serial
> 6000-9000ms 300-700ms
Michael,
I tried your programs on Windows and Linux. On Windows 98 the USB tower
takes about one second to reply (990 - 1100ms). On Linux it took about 9
seconds as you indicate. This looks like a problem with the Linux USB
driver. I will ask the authors of the driver (Juergen Stuber and David
Glance) if they have any idea what is causing the delay.
> What can I do to decrease the response time in the first case with
> the USB tower? Is it a problem of the driver or can I set the USB
> tower to be always active? ("port.setListen( true )" doesn't help)
setListen does nothing on USB towers, as I did not think it was necessary to
keep the usb IR Tower alive. The serial tower needs the keep-alive messages
that setListen sends, as messages from the RCX to the PC don't wake up the
tower. I could make setListen keep the usb tower alive if it is necessary,
but there didn't seem to be a need for this on Windows. As you probably
know, usb tower support is new on Linux in release 2.1.0.
Lawrie Griffiths
(The author of the josx.rcxcomm package).
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Message is in Reply To:
 | | Transmitting time USB vs serial
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| Hello, I use lejos 2.1.0 and legousbtower 0.52 from the lejos distribution. I measured the transmitting time of an Int from PC to RCX with the attached programs and got the following result: 1. single integer (LED at the tower is off before pressing (...) (22 years ago, 28-Dec-02, to lugnet.robotics.rcx.java)
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