2 Software. EMS CPC-PP

User Manual CPC-PP

2 Software

The software consists of two parts which communicate across the parallel printer port of the

PC. One part is executed by the microprocessor inside CPC-PP and can not be changed by the user. The application program runs on the

PC and makes use of the interface library.

2.1 Functions of CPC-PP

CPC-PP offers enhanced functionality for CAN communication:

• Transmission and reception of

CAN-messages

•

Filtering and buffering of received messages

•

Measurement of bus-load

The functions of CPC-PP are accessed across the interface library of the PC.

2.2 Application program: Realization concepts

The library of interface functions supports two ways to implement the application program.

The synchronous mode complies with conventional programming. The sequence of program steps is given by the program structure. Asynchronous mode allows event driven programming similar to the way used in graphical user interfaces.

EMS Dr. Thomas Wünsche 3

CPC-PP User Manual

2.3 Synchronous Interface main program

command initiation wait for result continue command execution by CPC-PP

The implementation of the main program with synchronous interface allows simple and clearly arranged programs with sequential flow. It is suitable mainly for simple applications, which allow a predefinition of events to process. This is true if, for example, only CAN-messages are to be received or only bus-load measurement is to be realized.

2.4 Asynchronous Interface main program

command initiation further program execution use result command execution by CPC-PP

The asynchronous interface provides enhanced flexibility in reaction to events which are not predictable in their sequence of occurrence.

Communication objects can be processed independently of program state, reactions can be configured flexible.

For this purpose every communication object is handed on to a set of handling functions. Such functions are provided within the programming library. The application programmer can add routines as required by application purposes.

4 EMS Dr. Thomas Wünsche