Programming Guide
for SOHARD drivers with RAW API

Version 2011-03-11, (C) 2000-2011 by SOHARD Embedded Systems GmbH, Fürth

The SOHARD RAW API drivers provide transparent access to ARCNET network with simple file oriented interface that is named "RAW API" interface

The RAW API provides following file functions:

• CreateFile (...) opens the driver
• CloseHandle (...) closes the driver
• ReadFile (...) or ReadFileEx(...) reads received packages
• WriteFile (...) or WriteFileEx(...) sends packets (data)
• DeviceIoControl (...) Controller initialization, Status information, etc., see list of IOCTL-Numbers below

For a more detailed description of these RAW API functions please consult the manuals of your compiler (WIN32-API Functions) or the SDK from Microsoft (see MSDN Library).

All necessary structures, types, constants, and feedback messages of the software driver (error messages) can be found in FARC.H.
You should include this file in your application.

For effective working it is recommended, that the driver is accessed asynchronously. Only in asynchronous mode it is possible to perform ReadFile and WriteFile at the same time ( see "Asynchon vs. Synchron").

Every description of the RAW API function provides a code example in "C" language. Futher examples in form of simple application could be found in RAW API SDK examples.

General Notes:

1) Have in mind, that the controller is capable of receiving 2 packets. No further buffering is done within the controller or the driver. The best way to ensure, not to loose any transferred data (broadcast messages) on the net, start a thread, that only performs ReadFile()-Operations. If a ReadFile completes with data received, store the received data, wherever you want and start the ReadFile again. It is good practice, to have 2 ReadFiles() permanently running in the above mentioned thread.

2) Windows is NOT a realtime operating system. Therefore it cannot be guaranteered, that the driver will always and under every circumstances read out the incoming data from the ARCNET controller before the next packets arrive. Heavy system load (i.e. swapping) may lead to loss of data (broadcast receives) and timeouts may occur on the transmitting station (EXCNAK), if ARCNET data is sent to the adapter on the Windows machine.