Axel, Thanks for your reply. But I am still having problems. I have written a short script to test the serial IO:

module SerialIO where

import IO

test :: IO () test = do com2 <- openFile "COM2" ReadWriteMode hSetBuffering com2 LineBuffering isOpen <- hIsOpen com2 putStrLn $ "hIsOpen = " ++ show isOpen putStrLn "About to send..." hPutStrLn com2 "l311" putStrLn "Hoorah!" hClose com2

Here is what I get when I run the test function using GHCi 5.04.2: *SerialIO> test hIsOpen = True About to send... *** Exception: failed Action: hPutChar Handle: {loc=COM2,type=duplex {read-write},binary=False,buffering=line} Reason: No error File: COM2 It appears to be connecting to COM2, but fails when it tries to output a character. The failure leaves the COM2 port connected, so I have to quit GHCi before I can use COM2 from HyperTerminal. I have also tried opening the file in WriteMode, and opening the port as "COM2:19200,8,N,1,P", but get the same failure each time? Do you have any other suggestions? Peter -----Original Message----- From: Axel Simon [mailto:A.Simon@kent.ac.uk] Sent: Thursday, 18 March 2004 4:54 AM To: Peter Pudney Cc: 'haskell@haskell.org' Subject: Re: [Haskell] COM port IO on a Windows machine? On Wed, Mar 17, 2004 at 05:46:25PM +1030, Peter Pudney wrote:

I have a microcontroller connected to the COM2 port on a Windows machine, and want my Haskell program to interact with it. My Haskell program is working nicely on my Mac, with interaction using stdin and stdout, but I am not familiar with Windows and a quick Google search did not give me any information on how to get Haskell IO happening through a Windows serial port.

* How should I open the COM2 port? IO Mode? Buffering?

* How do I write and read?

I presume I can set the port parameters fusing something like:

...; e <- system "MODE COM2 19200,*,N,1,P"; ...

You can also set these default parameters somewhere in the Control Panel. In case the openFile function is implemented under Windows by calling "CreateFile" in the Windows API, then you can just call openFile with the name "COM2:19200,8,N,1,P" or simliar and use standard read and write functions on files. Maybe this helps, Axel