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I've looked at implementing an interface for RobotC, but I've always
struggled with why bother since there are no applications that connect
to it.
I wish LEGO had implemented an option to provide a logic level "RS-232"
UART on port four. Yes, I know RS-232 defines +/-12V signal levels, but
there are many devices out there that, except for using logic voltage
levels, are identical to RS-232. This includes video cameras (CMUCAM,
AVRCAM) and a wide range of sensor MUXes, servo controller MUXes, GPS,
etc.
It looks like it would have been very simple to implement an additional
option for a logic-level serial link with some minor re-arrangement of
the existing I/O pins already used by sensor port 4.
You can't simply shift the RS-485 signals back to logic level because
RS-485 is half-duplex and it's not easy to tell the direction of
transmission. Most of the devices mentioned above require full-duplex
links. A full duplex link would make it easier to interface to many of
the devices mentioned above.
LEGO has defined baud rate of 921,600 bps for the RS-485 link. But since
any application is going to require custom firmware, this could easily
be changed to whatever you want within the hardware capabilities.
The one application that I can think of is connecting two (or more) NXTs
together. This would give similar capabilities to that available via
existing Bluetooth but at a higher bandwidth and much lower latency.
-----Original Message-----
From: news-gateway@lugnet.com [mailto:news-gateway@lugnet.com] On Behalf
Of John Barnes
Sent: Sunday, April 08, 2007 9:20 AM
To: lugnet.robotics.nxt@lugnet.com
Subject: Re: Using NXT Port 4 EIA-485
In lugnet.robotics.nxt, Christian Mock wrote:
> Hi,
> is there currently any software-support (pbLua, NXT-G, NXJ) for NXT • Port4 highspeed serial communication (EIA-485)?
> Thanks for more informations
> Christian
As far as I know, there isn't any support for this interface (RS-485
sensor port 4) in either the standard firmware or any of the other third
party firmware implementations.
The interface runs at 921,600 bps so it will be fast enough to be really
useful. I am hoping that, eventually, it will be supported.
JB
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Message has 1 Reply:
Message is in Reply To:
 | | Re: Using NXT Port 4 EIA-485
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| (...) As far as I know, there isn't any support for this interface in either the standard firmware or any of the other third party firmware implementations. The interface runs at 921,600 bps so it will be fast enough to be really useful. I am hoping (...) (18 years ago, 8-Apr-07, to lugnet.robotics.nxt)
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