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Thankyou very much Martin, that worked like a charm except for the
lnp_addressing_write(data,length,dest,srcport) which works as
lnp_addressing_send(data,length,dest,srcport)
Probably just a typo just thought I better let anyone else know who maybe
interested.
Now all I have to do is make that webpage about lnp :)
Michael.
In lugnet.robotics.rcx.legos, Martin Cornelius writes:
> Michael Marklew wrote:
> >
> > Does anyone have an example or two of using LNP so two RCX units can
> > communicate with each other?
>
>
> To get a somewhat crude explanation of how LNP works, and how to make
> RCXs with different LNP-Hostaddresses, i'd suggest to read thread 'LNP
> Addressing Schemes', last week in this newsgroup.
>
> However, if you don't need addressing or several ports, just do:
>
> on the receiving RCX:
>
> // create a handler function that will receive broadcast packets:
> void my_integrity_handler(const unsigned char *data, unsigned char len)
> {
> // process packet here
> }
>
> This function will be called whenever a broadcast packet arrives, and
> will get passed the packet as parameters.
> BE AWARE this function is called inside the IRQ-handler. It should be
> reasonably short and not do anything that could block, such as waiting
> for semaphores.
> This means, most of the multitasking functionality ( sleep, wait, e.t.c
> ), and sending LNP-Packets can not be used inside the handler. However,
> writing to the display, playing sounds, and switching outputs is O.K.
> If you must do some really complicated processing of packets, you should
> just save them inside the handler to a global array, and post a
> semaphore that wakes another task to do the real work.
>
> // activate the handler
> lnp_integrity_set_handler(my_integrity_handler);
>
> on the sending RCX there is nothing to prepare, just:
> // send packet
> lnp_integrity_send(packet,length);
>
> for bidirectional communication, you have to install handlers on both
> RCXs, of course.
>
> If you have more than 2 RCXs and/or want several ports, you first have
> to give the RCXs different host addresses -- read the thread cited above
> for info on how to do this.
> in this case, the handler function to install has one more parameter -
> the originating address.
> // addressing handler
> void handler(const unsigned char *data, unsigned char len, unsigned char
> src_address)
> {
> // process packet
> }
> //it must be activated with:
> lnp_addressing_set_handler(port,handler)
>
> The handler will be invoked whenever a packet arrives that is destined
> to this host and to the port given, port is a number from 1 to 15 (0 is
> reserved for dll )
>
> //sending of an addressing packet is done via
> lnp_addressing_write(data,length,dest,srcport)
>
> // length of addressing packets MUST NOT exceed 253 bytes !
>
> all this stuff is declared in include/lnp.h
>
> If you want PC's to participate in communication,
> - install a recent version of Linux ( kernel 2.2.x, glibc 2.x )
> - get the lnpd&liblnp packet from arthurdent
> - follow the instructions in the README
>
> that´s it - hope it helps a little, Martin
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Message has 1 Reply:
 | | Re: LNP Example please
|
| (...) hmm, really strange, in my legOS-distribution the name of the function is lnp_addressing_write, there is no function named lnp_addressing_send -- where have you got your legOS ? (25 years ago, 8-Feb-00, to lugnet.robotics.rcx.legos)
|
Message is in Reply To:
| | Re: LNP Example please
|
| (...) To get a somewhat crude explanation of how LNP works, and how to make RCXs with different LNP-Hostaddresses, i'd suggest to read thread 'LNP Addressing Schemes', last week in this newsgroup. However, if you don't need addressing or several (...) (25 years ago, 7-Feb-00, to lugnet.robotics.rcx.legos)
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