So if this card also doesn't support "full modem support" whatever that means then SerialPort is incompatible with this card? But a terminal emulator like Docklight handles it transparently I checked SIIG's support pages but their download-driver is the same version as the one I installed from their disk. These settings are accessed via 'Properties' from the Device Manager.
I can also use Boos. After much Googling it appears MS support or lack of it for serial ports has always been less than stellar. So unless someone has some magic configuration for NET's SerialPort that I haven't tried - I think its safe to say this thread is dead. And if anyone else arrives here with a similar problem my advice is to look for an alternative to NET - because it "can't get there from here".
I agree totally. I have had many issue with the Microsoft serial interface since the days of DOS. Microsoft doesn't know how to write a proper UART driver.
Sign in. United States English. Ask a question. Quick access. Search related threads. Remove From My Forums. Asked by:. Archived Forums. Visual C. Community Bot 1 1 1 silver badge. NET Framework. One silly question: Have you confirmed that the device the peripheral actually sends out something on the wire? If yes, showing your code will help us to help you : — user I see you send a signal almost immediately after sending, and the read value will possibly be 0 the first time the signal is trapped.
If I understand the code correctly, the next time a read is done will be when you send something and send a signal again.
Read is the number of bytes actually read by the method see msdn. It was originally used to offset into the buffer. Show 3 more comments. Active Oldest Votes. Sleep 15 ; SerialPort. The waiting is required to deal with the RS channel turning around. While the transmitter is enabled, DTR false , the slave cannot send, but the setting is required to get the message sent. The delay needs to be tuned to the duration of the sent message at bps, 10 bytes takes just over 10 ms.
Serial timing is difficult on multiplexed channels with a high-level API. Pekka Thanks for the comment. I hadn't thought in terms of bitrate to compute the required sleep time, it should help me improve reliability. Add a comment. Sign up or log in Sign up using Google. BytesToRead property. This property returns the number of bytes in the input buffer that need to be read. With this we could set up a loop that will skip over the read code if there is nothing in the input buffer.
What if you were creating a large complex program that was handling many tasks and would not be able to work within the confines of an infinite loop? Luckily for you, the SerialPort class has created an event that is raised whenever there is new data in the input buffer. In our case when data is received by the input buffer, the event will stop the program, call a method where we would most likely handle the data, and then go back to where our program left off.
We will delve into this in the next step. The first thing we need to do is to tell our serial port what method to call when it receives data. This is done with the following line: mySerialPort. DataReceived represents the method that is called to handle the event. Just one more note: you will want to make sure when using events that you declare your SerialPort object as a class level field so that you can use it in multiple methods including the event handler.
Different methods and procedures fit different situations, so you will have to find one that works and that you like to use. I personally like using the events whenever possible since they are the most efficient and leave the program free to do other things, but everyone has their preferences.
In the next step I am going to talk about how to write to a serial port. Good news! Writing to a port is incredibly easy! The other two write methods are also similar; the only difference is the data type of the data to send.
To use them, you provide an array of bytes or characters which will be written to the serial port. The offset parameter just specifies what element of the array to start at i. If you pass it 0, it will start at the very beginning of the array; if you pass 1 it will start at the second element. The length parameter is simply the length of the array.
Remember to perform these write operations within a try-catch block because they readily throw errors. The same concept is applied to Write and WriteLine. If we want to recognize them as characters on the hardware side you must have your own decoding logic present there.
I hope this is helpful to you and your next project. This was something that I personally struggled to figure out so I hope that this will help you have an easier time learning how to interface over a serial port. Feel free to post comments, questions and feedback below.
I have worked through the hardware permissions on the pi but cannot get access to the USB port through System. Thanks very much for responding, I wasn't sure how old this post was. Since the ports most likely would be different on other systems using this program, I have a separate program that reads and writes configuration data to an SQL database.
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