MQX™ CANopen Master/Slave for Embedded Devices

CANopen is a CAN-based higher layer protocol. It was developed as a standardized embedded network with highly flexible configuration capabilities. CANopen unburdens the developer from dealing with CAN-specific details such as bit-timing and implementation-specific functions. It provides standardized communication objects for real-time data (Process Data Objects, PDO), configuration data (Service Data Objects, SDO), and special functions as well as network management data. MQX Embedded's CANopen Master/Slave protocol software contains all the functions required for the implementation of CANopen slave or simple master devices. It is fully integrated with MQX Embedded's MQX™ RTOS for an excellent out-of-box experience. MQX Embedded's CANopen Master/Slave software is licensed royalty free with full source code provided.

MQX CANopen Highlights

• Comprehensive range of functions based on the current CANopen specification DS301 version 4.02
• Enables quick and easy development of CANopen devices (slave and master)
• Modular software structure with comprehensive configuration and scaling possibilities
• Clearly structured, simple programming interface for connection of the application program
• Integration with MQX RTOS and CAN drivers

Object Dictionary & Programming Interface

MQX Embedded's CANopen software provides a programming interface between the application tasks and CANopen protocol stack. This interface is implemented on the basis of mailboxes. Commands are transferred from the application to the CANopen protocol stack and the results of the command execution, events and emergency messages are passed from the CANopen protocol stack to the application. An application can consist of several tasks, which can use the CANopen interface independently of one another. Data is exchanged between the application and the protocol stack using the object dictionary. Each object dictionary entry can be directly allocated a reference to a variable with application data. PDOs and SDOs access these application variables directly. User-specific call-back functions can be connected to each application object and enable an event-controlled signal to the application when these objects are accessed. This mechanism allows direct, application-specific reaction to changes in application data triggered on the bus-side.

Process Data Objects (PDO) and Service Data Objects (SDO)

The MQX CANopen Master/Slave protocol software supports the PDO transfer types asynchronous, synchronous (cyclic and acyclic) and on request (RTR-Only). PDO-mapping can be implemented statically or dynamically according to the reaction speed required or available resources. Dummy mapping is provided as well as variable inhibit times. In addition, the protocol software supports multiplex PDOs. With SDOs, the transfer types expedited and non-expedited (segmented) as well as block transfer are supported. The application can check the data written by SDO for consistency before the target variables are overwritten and abort the SDO transfer if necessary.

Network Management

MQX Embedded's CANopen Master/Slave software provides all network services required to implement a simplified bootup procedure and includes support for bootup message, node guarding with or without life guarding (master monitoring) and heartbeat mechanism with producer monitoring.

Identifier Allocation

Identifiers are allocated by default according to the predefined I/O connection set but can also be assigned by altering the relevant object dictionary entries.

Master Functionality

MQX Embedded's CANopen software package also enables the implementation of a simple CANopen master with its own object dictionary. A CANopen device implemented on this basis can work in a system either as a slave or as a master and be configured via the object dictionary. The software package provides the basic functions for the NMT services. Functionality such as the control of the system bootup, verification of the availability of all required slave devices, automatic download of configuration data or also specific reaction to node failures can be programmed by the user.

Supported Processors and CAN Controllers

The MQX CANopen Master/Slave protocol software is available for the following Freescale Semiconductor processors and (CAN controllers):

• Power Architecture MPC5200 (MSCAN)
• ColdFire MCF5282 (FlexCAN)
• ColdFire MCF548x (FlexCAN)
• ColdFire MCF523x (FlexCAN)
• Power Architecture MPC5xx (TouCAN)