[RESOLVED] MSComm Woes

When the user plugs a USB device into the computer, my program checks in the registry for the Port the driver has used (usually the next available, on my system Comm 5).

I use the MSComm control to open a communication with a chip on an electronic device. It works great, I use a GUI to perform hyperTerminal operations.

My customers OS (XP Pro) tries to use port 17, and the program fails to communicate with the device, although HyperTerminal will work.
According to the VB Helpfile the MSComm control can only use ports 1 - 16. Is there any other way around this??

I need a fix which doesn't involve users messing around with hardware settings, I need to do it all via my program.

Thank you

http://search.msdn.microsoft.com/sea...0&query=mscomm

Thanks for the link, but I'm familiar with basic MSComm settings. I was really needing a windows API I can use, or another way of communicating via the comm ports if anyone knows another way of doing it besides MSComm.

Thanks.

I can now open the port using an API. Can anyone tell me the method for sending strings to a com port without using the MScomm control?

Have a look at this thread

Thanks Frans,

that link has been a great help, I can now open a port higher than 16 and send characters to a chip onboard an electronic device via that port.

The example in the link sends a character array. My chip is expecting a string in a specific format. Using the MSComm control I simply had to send the string "C1103345123401" & chr(13) for the device to be happy and respond accordingly.

I can't work out how to do this using the writefile function as in the examples in the link. Can you or anyone else please point me in the right direction. I need to pick up the string returned by the embedded chip also.

Thank you.

It should be as simple as calling the Write2Port function, with "C1103345123401" & chr(13) for the strData parameter. The conversion to byte array is already in there. I have never tested it though. I just remembered the thread from a previous visit, and found it back with the search function.

Doesn't it work?

The chip is expecting a string followed by the chr(13). If successful it replies with an audible beep and sends back an "OK" & chr(13) string.

I can only get it to beep if I send a single "control" character to it. For example an "X" & chr(13) forces a beep and a 52 character string return string with all current settings and its set serial number.

Also I'm not sure how to retrieve the return string using the API's. I may have to abandon the API approach.

Thanks for your help though.

VB Code:

Declare Function ReadFile Lib "kernel32" Alias "ReadFile" (ByVal hFile As Long, lpBuffer As Any, ByVal nNumberOfBytesToRead As Long, _
                                                           lpNumberOfBytesRead As Long, lpOverlapped As OVERLAPPED) As Long

may be of some help. http://www.allapi.net/apilist/ReadFile.shtml