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jcurl / RJCP.DLL.SerialPortStream

SerialPortStream is an independent implementation of System.IO.Ports.SerialPort and SerialStream for better reliability and maintainability. Default branch is 2.x and now has support for Mono with help of a C library.
Microsoft Public License
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How to access response data #31

Closed agidden closed 7 years ago

agidden commented 7 years ago

If we use SerialPortStream to send characters to a COM port with WriteLine, we cannot get the response sent back. The DataReceived event never fires and there is no data when we call Read after WriteLine, even if we wait for a few seconds. There are no examples showing how to do this, and even the test code doesn't show how this is done. Is it possible to get the response somehow?

jcurl commented 7 years ago

You use it like you would the MS implementation. If you're running a 32-bit system, you can use PortMon. Look at the wiki page on Tracing to get logs and post them here.

There's always a few things you can do and build yourself a simple Y-Cable and use a couple of USB-SER ports to monitor what's being sent and received.

If there's no Read when sending data, then it could be very well that the data being sent is not in the right format (check newlines), or your device is not sending (do you need to set any flow control?)

agidden commented 7 years ago

Thank you for the quick response. Since the DataReceived event is provided we assumed that it would work with a response, but it appears it does not. The only other option is to look in the Read buffer, but it is empty. We know the data is being sent and that a response is being returned, we just can't figure out how to get the response, or make SerialPortStream give us the response.

Looking at the MS implementation, it appears this is accomplished with a 'read' thread. Not a problem, but we were hoping to use SerialPortStream to avoid the MS issues.

jcurl commented 7 years ago

Hi, I need you to provide a trace as I provided the link earlier. Then I might be able to see what is going wrong.

jcurl commented 7 years ago

Any logs?

agidden commented 7 years ago

Thank you for following up with us on this issue.

We used a serial port test program to verify we were being sent responses. We also verified that the data we sent via SerialPortStream was being received and acted on.

We are trying to send commands to an industrial marking device. I cannot share any details of the implementation, including log data.

The commands are a string of 1 to 8 characters terminated with a newline. The same string of characters terminated with a newline will be in the response, if there was no error.

Our code used three patterns:

On Sat, Jul 15, 2017 at 2:07 PM, Jason Curl notifications@github.com wrote:

Any logs?

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/jcurl/SerialPortStream/issues/31#issuecomment-315555305, or mute the thread https://github.com/notifications/unsubscribe-auth/AYZ3WRzlX-gzl6Miv7gbyw9_8r6D25Wmks5sOQ3bgaJpZM4ORZtP .

jcurl commented 7 years ago

I'm sorry that I can't help you any further. To do so I would need logs as generated by my software using the tracing link I've provided earlier. Your issue refers to no data being received at all. This sounds like a custom driver provided by your manufacturer that doesn't fully implement the serial driver in asynchronous mode.