I want to use Bluetooth(4.0) on my board to transmit it's Name so any Mobile Application can see it's name and Mobile application initiates the pairing and connection with my Bluetooth.
I have seen some examples of Bluetooth(4.0) scanning nearby devices; For example:- It does scan for Bluetooth Mouser/Keyboard, but in this case Bluetooth(4.0) is in mode where it chooses the device it want to connect while I want it reverse so Any mobile application can see my Bluetooth and gets connect with it and does communication.
How can I put my Bluetooth(4.0) in such mode in Linux? Is there any C library using which I can put Bluetooth(4.0) is the mode where it goes in Bridge mode instead of scanning nearby devices?
You can set the name of your device like this:
hciconfig name "foo"
and check your name with:
hciconfig name
You also have to enable Low Energy advertising for your device to be found by others:
hciconfig leadv
You can configure your device to accept incoming connections like this (lm for link mode):
hciconfig lm MASTER,ACCEPT
This way the kernel will accept a connection, even if there are no listening sockets.
Considering you want to do actual communication, you would need to write a program, accepting the connection and sending/receiving data. Just putting your device in a mode where other devices can connect to it isn't really worth anything (because you can't communicate).
The basic principle is to open up an L2CAP socket, with the Channel ID of 4 (for Low Energy), then do standard bind/listen/accept. I suggest you look at the source code of Bluez and the examples.
Related
I'm using a LPC178 development board and I want to read a file present on a Windows PC. My dev board only has a RS2323 interface to communicate with.
How can I go about transferring the file from my PC to my MCU using a RS232 (serial) link? I found a reference which explains how to transfer data between a MCU and PC but it isn't about file transfers.
Afaik there is no easy solution for this like calling something like "copy" or "fopen" over RS232. I would be happy to be proven wrong here.
The fastest solution might be to write a little programm running on your Windows Host, which listens to your RS232 communication and pipes your communication into/out of the file based on your communication protocol. This can be done with standard file operations in the language of your choice, for example C, C++ or Python.
Your problem is one of the oldest in the book. How do you transfer files without fancy operating system abstractions. For RS232 (or any other serial method) there exists many file transfer protocols.
One of them is kermit. This is a protocol from 1981 and can transfer binary and text files. It is able to be embedded in a micrcontroller and there exists programs to transfer/receive using kermit.
alternative old site for reference
In the simplest case you would use a file transfer protocol such as XMODEM, YMODEM, ZMODEM or Kermit - these protocols were designed in the days before networking and the Internet were ubiquitous and deal with simple point-to-point transfers between two computers. They are supported bu most terminal emulator tools such as TeraTerm Pro or PuTTY so no specific PC software need be written, just the microcontroller end.
A more complex but flexible solution is to implement a TCP/IP stack and a PPP driver, and an FTP application layer - probabaly only practical if using a third-party TCP/IP stack and application layer. You can then use any FTP client for the PC end, so again no PC software required. While this may be overkill if all you need to do is transfer files, it has the advantage of allowing you to use the the single serial port concurrently for other data streams and application protocols such as Telnet. The disadvantage perhaps is that while Windows does support PPP it is buried within the dial-up networking and to be frank a pain to get working.
Very first step you have to do is ensure serial communication is working fine.
Send a byte continuously from mcu to PC and display it on some io console (for example: HyperTerminal, Dock light )
Receive a byte to mcu from PC and echo it back to PC.
Once you are sure that serial communication is working fine then select some file transfer protocol and implement it.
While you can select any of the available protocols or write your own protocol and implement it.
For purpose of discussion i select Xmodem protocol.
If you consider some other protocol you may stop reading answer here.
XMODEM is a simple file transfer protocol.
Refer http://web.mit.edu/6.115/www/amulet/xmodem.htm for detailed information.
You may implement Xmodem mcu side by reading protocol. Or may consider using open source also ( if available )
PC side i prefer to use HyperTerminal io console as it is compatible with Xmodem.
In HyperTerminal all that i have to do is configure settings and select file for transfer to mcu.
Now transfer any file to mcu using Xmodem protocol from PC.
What you do with received file in mcu is up to you : )
Now I'm trying to make embedded Linux system act as Bluetooth SPP server.
In the system, blueZ can be used and I've already checked bluetoothctl command is enabled to scan, pair and connect with some bluetooth devices (iPhone and mac book).
However, in spite of searches, there is no information to make Linux as Bluetooth SPP server with automatically paring and connection. I'm trying to realize the use case below:
(1) Some setups on the Linux system (enabling bluetooth daemon, hcitool, SPP server, and so on...)
(2) The client device scans the Bluetooth (Linux). If found, it tries to pair.
(3) When pairing request received, the Linux system will pair the client device.
(4) The client device tries to connect the Linux system.
(5) The Linux system allows to connection.
I want to know whether or not this use case is realizable, and if possible, I'd like to know some tutorials or sample codes.
The best case is that I can realize the use case above with C (or C++) programming using BlueZ (dBus API).
I am planning to use Dump1090 and I want to have 2 RTLSDR dongles on the same computer, always plugged into the same USB port. I am planning to assign a symlink "adsb" to the port for the RTL dongle that has an ADS-B antenna connected to it. Is there a way to force the connection on this specific USB port?
By default, the code takes the first device available.
Thank you
https://github.com/antirez/dump1090/blob/master/dump1090.c
I am trying to implement Bluetooth using "connect-blue-oem-spa-331" module using UART protocol and using MSP430 as base controller. I'm using Embedded C as a language of programming.
Everything just works fine until I reach to Serial Port Link Command "AT*ADCP". Every time I get response as ERROR. I have tried with both options by keeping ECHO ENABLED and ECHO DISABLED.
p_cmd = "AT*ADCP=XXXXXXXXXXXX,0,0,0\r";
this is my command. 'X' represents the Bluetooth confirm device address which I confirm when I execute DEVICE_INQUIRY command.
The module through which I am executing all these commands is always MASTER and will initiate pairing and communication process. As a safety I have kept it non-discoverable.
How can I implement the Serial Port Profile Link command without getting error when I confirm the bluetooth device using DEVICE_INQUIRY command.
I have been working with blue tooth for last 4 months. I had faced above issue in early days. And after running through documentation available for product I solved the issue. I thought to reply this question which I've asked.
I was using Connect Blue OEM-SPA-331i classic Bluetooth module in my project, and was using Serial Port Profile to implement Bluetooth commands.
When I inquire devices I get the list of Bluetooth Devices available and discoverable in the vicinity(mine was CLASS-I Device); and lists them as (48 bit MAC Address,Class of Device) i.e. ( 001234ab987f,786545) of the discovered Bluetooth Module.
When I'm trying to establish Serial Port Profile Link, it was required that I must write address of peer device to be connected over Serial Port Profile in Serial Port Adapter. The order of the commands should be
Inquire discoverable devices
Write the desired peer device address to Serial Port Adapter, remember it in power cycles.
Establish Profile Link.
This way I resolved my issue of link not getting established.
I have an ECR(Electronic Cash Register) device,it has a RS-232 com port cable for the connection to PC but I have not been given any drivers for it. I am trying to connect the device to PC but PC is not able to detect the cable. How to detect this device attached on this RS-232? I am working under Linux. Any help on how to find the device is appreciated?
Following is the code snippet I found in C to connect to device based on Baudrate and Com Port number.
int OpenComport(int comport_number, int baudrate)
int SendByte(int comport_number, unsigned char byte)
int SendBuf(int comport_number, unsigned char *buf, int size)
Please see my answer to a related question which shows how to open and configure the serial port.
On Linux, serial ports are almost always /dev/ttyS[0123] (that is /dev/ttyS0, /dev/ttyS1, etc.) for the hardwired ports, and /dev/ttyUSB* for USB ports. The hardwired "devices" may appear only when the hardware is present on some distributions. On others, they always appear whether there is hardware or not. (Try cat /dev/ttyS2 and see if you get the error "no such device".) This is a kernel configuration option which is frequently set to create the device entries whether the hardware is there or not.
The USB ports are present only when there is hardware plugged in, but if there are multiple USB serial ports, it can be difficult identifying which is which.
There is a mechanism within /etc/udev/rules.d/* which can be configured if some aspects of the devices are consistent. See man 7 udev for details.
For applications I have written, I determine which device is which by writing to the device and identifying its response. For devices which don't respond, this is either a worthy programming challenge or a mundane configuration solution.
I think you need to do a little reading about RS-232, and well, C programming also. There are no drivers for RS-232. It is a very "dumb" protocol - you basically just shove data out the port.
The PC cannot detect the cable? That's because it's not USB. Believe it or not, Plug-and-play didn't always exist; you tell the software what port the device is supposedly connected to, and it tries to talk to it.
Furthermore, those aren't "code snippets", those are just function prototypes. There isn't any actual code there.
1>since there's no operating system on your ECR so I guess u don't need any drivers ,instead a firmware will be there in the ECR , which tries to communicate with your Linux UART driver
2> Rs-232 is basically a serial protocol , I mean it has 9 wires , and hence a connecter with 9 pins are used DB-9 connectors ,all the communications inside a processor is in parallel format so a chip called UART is used to convert all the parallel data into serial data , and since yu want to pass the data in Rs-232 format , it needs to be packaged in that format .
3> Linux kernel already has a uart driver , which is implemented for RS-232 . so need to worry about drivers from Linux side.
4> Open a terminal type " dmesg | grep tty " ( connect only the ECR to the PC for rs-232 ports ). it will return something like ttyS or ttyUSB etc , however u just concentrate on ttyS if u have connected only through rs-232 cable .
5> Once u are sure of the ttyS device from the dmesg use minicom (its easy to use ) to communicate with the device.
regards,
Zubraj