I want to get comport on my PC without connecting any peripheral device and outputs from there like some device attached to that port. Can any software do that or commands can do that for me?
Here you can find a free application which can emulate unlimited number of ports and send one port output to another's input.
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Currently I have a server, that communicates with a projector through a RS232. The server opens a com port when the projector is connected. The same happens to any PC when a certain type of device is connected through the USB (lets say an Arduino for example). What I want to do it basically replace the projector with a PC/Arduino/Raspberry without the server noticing anything. That would mean the server will recognise the connected PC and open a COM port for it. What do I need to do on the PC so that it automatically opens a com port on the server? I guess there is something very basic that any printer, Arduino, projector etc does, that computers recognise it as a "com port device".
P.S. Doesn't matter the OS on the PC, I just need to make it work and then implement w/e I need to do with the established communication over the port.
P.S.2 I've searched a lot about it, but probabl I am doing it wrong, because I didn't find my type of question anywhere.
COM ports are basically hardware that is detected by the system. Let's say, if an Arduino is connected to a PC, it has its onboard USB to TTL converter which can be found in the device manager(if using windows). Similar USB to TTL converters are there in the market like CP2102, PL2303 which acts like a COM port even if no device is connected further to it. it may be possible that the program you are using(as you referred server) may be sending some data over the serial port and verifying the hardware.
What you need to do to replace it is, first of all, find the baud rate at which the communication is going on, then, listen over the serial lines which machine is sending which message in the sequence(there must be a handshake as I mentioned earlier), if a complicated algorithm is not used by the device, you can simply mimic the device by sending same messages over serial.
I have 16 Arduinos that are in very tight spaces and hard to get to when I need to reprogram them with my FTDI cable. I would like to have or create some sort of centralized place where I can connect my FTDI cable, make some sort of selection (switch of some sort), which will then connect the pins my cable is on to the selected arduino.
Does anyone have any thoughts on how this can be accomplished? I've toyed with transistors, but that takes a lot of them and didn't quite work.
Are there any premade solutions that are out there that I have yet to find?
Thanks very much!
Here is a thought! TCP to Serial.
Sound complicated.
Not really.
Note from AVRDUDE's manual the following
For programmers that attach to a serial port using some kind of higher
level protocol (as opposed to bit-bang style programmers), port can be
specified as net:host:port. In this case, instead of trying to open a
local device, a TCP network connection to (TCP) port on host is
established. The remote endpoint is assumed to be a terminal or
console server that connects the network stream to a local serial port
where the actual programmer has been attached to. The port is assumed
to be properly configured, for example using a transparent 8-bit data
connection without parity at 115200 Baud for a STK500.
With this, One could place your Arduino's behind your choice of TCP to Serial Server. Which is available in several forms. Cisco has a gang TS (but that is expensive, unless used). lantronix (and others have single end point devices. But then for Linux, there is "Net2Ser" which can serve up all your ttyS (aka Serial/COM ports).
With the later you could use a raspberry or TP-Link TL-WR703N (
In the latest IDE 1.5.6r2 add one entry for each TCP-to-Serial Port to ./Arduino/hardware/arduino/avr/programmers.txt file. While replacing the IP and Port with corresponding values.
TCP2001.name=TCP 2001
TCP2001.communication=serial
TCP2001.protocol=stk500v1
TCP2001.program.protocol=stk500v1
TCP2001.program.tool=avrdude
TCP2001.program.extra_params=-Pnet:192.168.1.100:2001
TCP2002.name=TCP 2002
TCP2002.communication=serial
TCP2002.protocol=stk500v1
TCP2002.program.protocol=stk500v1
TCP2002.program.tool=avrdude
TCP2002.program.extra_params=-Pnet:192.168.1.100:2002
...
Additionally change "protocol" to "upload.protocol" the following line in ./Arduino/hardware/arduino/avr/platform.txt
tools.avrdude.program.pattern="{cmd.path}" "-C{config.path}" {program.verbose} -p{build.mcu} -c{protocol} {program.extra_params} "-Uflash:w:{build.path}/{build.project_name}.hex:i"
to
tools.avrdude.program.pattern="{cmd.path}" "-C{config.path}" {program.verbose} -p{build.mcu} -c{upload.protocol} {program.extra_params} "-Uflash:w:{build.path}/{build.project_name}.hex:i"
With this you can use "Upload Using Programmer" with the selected programmer to send over TCP, rather then use the Upload.
That all said, it will only work on Linux.
avrdude: ser_open(): network connects are currently notimplemented for Win32 environments
I develop a app which discovers a network topology and draw it programmaticly with java and SNMP4j
I send CDP and LLDP requests to devices and analyze result of this. However there are devices which has not support CDP or LLDP(like Access Point) therefor I cannot discover it. I must show it as unkown device.
Thanks to CDP and LLDP I know which device is on which port. To understand unknown device is on which port,
I need a oid to learn up and down ports of the Switch with SNMP or another method.
I use SNMP4J
The table dot1dTpFdbTable (1.3.6.1.2.1.17.4.3) shows which MAC addresses can be reached on which ports.
Two things to watch out for: it is not supported by all devices and it does not only list the connected devices but also everything connected to those devices.
I am trying to connect ATmega128 uart to PC using USB-to-RS232 converter so that PC can receive and transmit data from microcontroller using hyper terminal. I set the correct stop bits and baud rate in hyper terminal. It doesn't seem to work.
Can any one tell me if this is possible by USB-to-RS232 converter and if not what other options are there for serial communication between PC and microcontroller ?
You should be able to do this without any issues. I'd suggest putting your USB-to-RS232 cable in loopback mode first (if possible) to ensure you can communicate, then connect it back up to your MCU.
If you aren't seeing what you expect the first thing to look at are the settings, specifically the baud rate. Since your USB-to-RS232 cable is from a third party vendor I'd assume that your settings on the host side are OK. So you should look in to your MCU code to ensure that all your clocks are running at the proper speed and you have indeed performed the correct calculations to achieve your desired baud rate. Debugging here to ensure you are transmitting data out of the device is important.
Additionally, there are tools that can help you debug. Portmon is a tool from Microsoft that lets you look at the serial data path on the host side. I'd also recommend a USB analyzer, such as an Ellisys, that will allow you to view data going across the line from your MCU to the host.
I want to know some general communication strategies, which should be followed for a communication via COM (serial) Port.
I can read/write at the port, also can list all the available ports on the machine. I'm using Qt C++ with QSerialDevice. For testing on a windows machine with no physical serial port, I'm using VPSE (virtual port)
Typical Flow (assumed):
List all the available serial ports of the computer.
Find out at which port my device (micro-controller) is connected - how to do it?
Device found.
Start a thread for reading from the port, another thread for writing it.
Safely close connection
Finding out at which port the device is connected sounds challenging to me. How to achieve it? I guess, I will send a HELLO message to each ports, if my device replies a specific per-defined reply message I can be sure my device is connected at that port. Can I?
Also I think, to seperate threads are necessary because at any time I may receive message from the Micro-controller device.
Thanks for helping :)