Internet Module / Socket Programming

Hi

I would like to communicate with the Raspberry Pi via the Ethernet port. Eventually using PIC devices as detectors sending data back to the
PI. The system would use the PI as a master polling each PIC slave detector asking if it has anything to report. The data packets would be quite small in size.

I have a couple of Pis to test software with or one end could be an Iyonix.

I have reasonable programming knowledge regarding RISCOS in C,BASIC,Assembler but have no knowledge of how to interface with Ethernet.

My initial investigations have led me to the following documentation.

http://www.riscos.com/support/developers/prm/internet.html
This has examples will these work with the PI?

I also have started :-) reading the Internet module in PRM5A, Is this documentation still valid regarding the PI.

These documentations mention the following libs:-
Inetlib
Socklib
Unixlib

I have also read about EasySockets module but I dont think this is 32bit.

I have the C/C++ compiler from RISCOS Open and the latest update is ROOL_DDE24.Hopefully that all I need.

TIA

Terry

Hi Terry,

I’ve used the ROOL compiler to write !NewsUK and !WeatherUK.
It’s fairly easy to do, I was meaning to write some tutorials on socket coding in RISC OS.

I’ll look at getting something up tonight here

Hi Malcolm

It would be great if you could do some simple tutorials to get people started not just for my own selfish reasons:-) I suspect
I am not the first and will not be the last to use the PI as some kind of controller.

If people can find the resources they need and are new to RISCOS they are more likely to persevere with the operating system.

Sometimes if the learning curve is to steep people will give up and use a different OS some of us :-) have a soft spot for RISCOS but
anything that brings attention to the OS is a good thing. I think RISCOS has great chances now it runs on the PI.

Regards

TIA

Terry

Some examples of programming using sockets with RISC OS would be great!

I’m just doing the client socket side at the moment, as that’s all I’ve done. But it should be enough to get people started at least.
I would appreciate some feedback about it malcolm at paymentlabs dot com

I’ve done the basic outline now for a client, but I need to add a fully working example.

Most (if not all) programming on RISC OS is pretty easy once you know what to do, it’s pulling it together that is a nightmare – or was for me.

One thing I would like to do is a bi-monthly meeting for RISC OS programmers in the North of England, a get-together and show of code (not that a lot of my code I’m that proud of ;-)) and bounce ideas around.
Not sure if there are enough interested people.
Location would be based in a central area to where the people are. I know one person who may be interested in Ormskirk and I live in Hull, there’s another possible in Leeds.
Pricing would be based on cost/people, but I’m sure we can get a reasonable price for say a Church hall for a couple of hours?
If enough are interested and we can get the numbers, it may be fun?

and another also in West Lancashire, but Leeds is a long way – and hull is on the other side of the world. The North of England is a big place.

If you are looking for a really quick way to implement Ethernet communication with a Raspberry Pi, then you could try using Wget on the client and cgi scripts with !Webjames on the server. You could have it up and running in 24 hours.

Works a treat – and the real benefit is that the method can also be used to communicate between different operating systems on different hardware.

@John, I don’t mind travelling to Manchester once a month. As I said it would need to central, but more to most of the people.

Manchester could be OK (near the M62?)

Keep us posted.

Hi Malcolm

Thanks for the tutorial, I think with this and the other documentation I
mentioned I should be able to get somewhere. It would be great if you could
supply a working example as its easier to tweak / break :-) a working example.

Anyway thanks for your efforts so far, Very useful

Regards

Terry

I’ve just released an update for NewsUK (not yet reached !Store yet).
The downloads are much quicker now. (Well they are for me, I have 75-175Mbit internet connection, which it now utilises better.)
One thing I’ve noticed is a problem that’s been there for awhile. Probably one in a hundred downloads causes a corrupt sprite.
I’m fairly sure this isn’t a changeFSI problem, as refreshing the download causes a correct image to display.
My assumption is that there is some logic missing from my downloading, however it is possible (I admit unlikely) that there is a bug in the RISC OS socket layer.
As it’s 1 in a hundred (or more), it’s not going to be really easy to reproduce – so I thought I’d ask if anyone has seen corrupt downloads with sockets on RISC OS.
As I said I’m assuming the fault lies in a simple logic flaw with my code somewhere, that I’m going to have to track down.
As with all programmers, laying the blame elsewhere is the easiest option ;-)

That’s welcome news, Malcolm. So, why are downloads much quicker? What did you do!?

Can’t say I’ve noticed a problem with corrupt images, but I’ll keep an eye out.

I’ve just released another update ;-) This one is far more exciting though! You can now use most of the BBC News Feeds (+ the main Sports feed, I hate sports but I figured it maybe popular with other people). I should add something to save which feed you are loading, and also allow changing of feeds mid-refresh.
But those can come later.
Downloads were speeded up by adding logic to say if the buffer is more than half full (I worked out around 12k out of a 18k buffer) then only do a “micro sleep” rather than the full sleep. Also if the buffer is totally full then return as quickly as possible to the program.
I added logic to store the previous DNS lookup, and if it is the same hostname and port as the one being asked for used the previous stored results.
I think I fixed the corrupt images download, which I think were due to reads if the socket stalled during reads, so I added specific logic as I think I missed any logic out before.

I hate sports but I figured it maybe popular with other people

Seems like a fair assumption ;-)
Not that I’d be interested in sports myself tho

Keep up the good work Malcolm!

In the original post, Terry spoke about this page
http://www.riscos.com/support/developers/prm/internet.html

I’d like to know where I can found the described library while acorn doesn’t exist anymore !

Their example use those includes (which are the same in Linux Workd :))

#include “sys/types.h”

#include “sys/socket.h”

#include “netinet/in.h”

#include “netdb.h”

Thank’s

The libraries are included with the DDE (in AcornC/C++.Export.APCS-32.Lib.TCPIPLibs). You can put “${NET5LIBS}” in your makefile to get the libraries and their dependencies.

Thank’s. But for the moment I do not use Makefile. How can I simply compile and link a simple c file ?

Wish I’d seen this ages ago. Just the plain old POSIX Linux networking interfaces are supported. It’s what I used when I started the uSynergy port.

One quirk to beware of: many versions of the RISC OS internet stack return the error number plain. RO5 returns it with the aded base value of 20E00 hex.