Tuesday, January 19, 2010

What an idea!

Yesterday i talked with an old friends! He helped me about finding a way to code "something". He is damn formal and accademic (and effective developers too), and i was so suprised on how two minds can works in sync.
So we started to chill around a lil project, which maybe we are gonna to develop...
The main was about "how to define an algorhythm as an XML documents". I guess we found a (maybe one of tons) solution an it is possible in the next days im gonna posting something more. It will be about BNF about a "certain" arguments, which will be translate as a XML-Scheme.
That scheme will be the data structure to work and interact with a web-based tool..
Nothing more, stay tuned..

Tuesday, November 3, 2009

Bluetooth Device Discovery in c language HOW TO

Today i wanna show a simple how to about bluetooth programming.
I will start witha brief theory follow by a full commented c source compile under linux.

This two functions convert a string address in a bdaddr_t (a defined structure which is a bluetooth device address) and viceversa
str2ba (const char * str , bdaddr_t * ba)
ba2str (const bdaddr_t * ba , char * str)
We also need to know about local bluetooth adapter, this functions will be useful:
int hci_get_route (bdaddr_t * addr)
Return the device id of the given bdaddr_t, you can pass NULL so it returns the first available device.
If you know the device's address you want to use you can pass it to this function
int hci_devid (const char * addr)
finally you can open resources to use the device you choose with
int hci_open_dev (int adapter_id)
Now you need to send an inquiry signal to receive information about the devices to respond.
You can do this by calling
int hci_inquiry (int adapter_id, int len, int max_rsp,
 const uint8_t * lap , inquiry_info ** devs , long flags
  • adapter_id = the adapter you choose before
  • len = inquiry time, the standard is about 8 * 1.24 (so len = 8)
  • max_rsp = maximum devices response (usually 255)
  • flags = usually IREQ CACHE FLUSH, if you pass 0 then previous inquiry info may be returned
  • lap = determine the type of inquiry, if you don't care give it NULL.
Be careful: devs parameter should be sized enough to store a max of max_rsp inquiry_info struct...
Sounds like:
(inquiry_info *)malloc (max_rsp * sizeof (inquiry_info));
And finally you can get devices friendly name, follow this how-to
  1. cycle hci_inquiry return step to check for the devices found
  2. look for bdaddr_t field in the devices list stored by hci_inquiry, converted by ba2str
  3. store enough memory to convert string address to string name
  4. get the name with:
    int hci_read_remote_name (int hci_sock, const bdaddr_t * addr,
     int len, char * name, int timeout)

And here the code:
 * bdd_main.c
 * This is a sample about how to discovery bluetooth device

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/socket.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
#include <bluetooth/hci_lib.h>

int main (int argc, char ** argv)
 inquiry_info * devices = NULL; // This struct will store the found devices
 int max_rsp, num_rsp; // max devices to find, devices found
 int adapter_id, sock, len, flags; // use to hci_inquiry and hci_open_dev, returned by hci_open_dev, 1.24 * len sec inquiry time, flags chache or flush
 int i;
 char addr[19] = { 0 }; // this is a middle to find out friendly name
 char name[248] = { 0 }; // this is to store friendly name

 adapter_id = hci_get_route(NULL);
 sock = hci_open_dev(adapter_id);
 if(adapter_id < 0 || sock < 0)
  fprintf(stderr, "Error code %d: %s\n", errno, strerror(errno));

 len = 8; // 10.24 sec lasts
 max_rsp = 255; // max of 255 devices to discover
 flags = IREQ_CACHE_FLUSH; // no use previous inquiry data
 devices = (inquiry_info *)malloc(max_rsp * sizeof(inquiry_info)); // malloc for devices

 num_rsp = hci_inquiry(adapter_id, len, max_rsp, NULL, &devices, flags); // inquiry
 if(num_rsp < 0)
  fprintf(stderr, "Error code %d: %s\n", errno, strerror(errno));

 for(i = 0; i < num_rsp; i++)
  ba2str(&(devices+i)->bdaddr, addr); // convert bdaddr to a string
  memset(name, 0, sizeof(name)); // memset to store friendly name
  if(0 != hci_read_remote_name(sock, &(devices+i)->bdaddr, sizeof(name), name, 0)) // store in name the first sizeof(name) byte of the friendly name of the given addr.
   // this mean the friendly name was not found
   strcpy(name, "[unknow]");

  printf("%s %s\n", addr, name);


 return 0;

Do not forget to compile linking bluetooth lib XP...

Saturday, October 24, 2009

Eclipse 3.5 SR1 Galileo (C/C++ IDE) devkitpro on Linux Mint 7

Im trying different enviorment on which devel. Today i wanna keep information i found on how to set up an linux eclipse c/cpp IDE for nintendo DS programming. Especially this work for Linux Mint 7 but i guess this should work for most linux distros.

If you try to install eclipse for c/cpp from mintInstall you will notice that it is an older version, which is not compatible with an interesting plugin:
NDS Managedbuilder

So the way you have to follow is to download the latest eclipse version from the official site.
Well you love to do it all by shell, so open up your terminal, look on the web the download link and get it.
Now you need to extract it everywhere you want in your filesystem. I dowload it in my home folder and extract in /opt/

~ $ wget <link>
~ $ tar -C /opt/ -xvjf <archivename>

And about eclipse it's all. You can launch it from there or link it eveywhere you want.

the latest link is: http://www.eclipse.org/downloads/download.php?file=/technology/epp/downloads/release/galileo/SR1/eclipse-cpp-galileo-SR1-linux-gtk.tar.gz.

Now we will move on the devkitpro getting started web-site. There is deeply and clearely explained how to install the toolchain.
It's easy, just build the filesystem tree, download the libraries and extract in the right folder.
You can finde the wiki here: devkitARM.

Well it's time to install the eclipse plugin so move to NDS Managerbuilder, open eclipse

Help > Install New Software > click "Add" button > http://dev.snipah.com/nds/updater

follow the instruction, restart eclipse and you are ready to develop for Nintendo DS (c/cpp too) on eclipse in a linux enviorment!

[EDIT] Stay tuned, gonna look to add PAlib too ;)