The Slave Node I/O Module Design Base On CANopen Communication

CAN fieldbus is very important as a member of the industrial field bus,it has reliability,real time,flexible and economic characteristics,has been widely used in the automotive industry,process control,textile machinery,agricultural machinery,robot,medical equipment,shipbuilding and other industries.CANopen is a high-level protocol structured on CAN communication,it not only possesses the advantages of CAN bus,but also has its own feature,such as perfect network management,fault management,real-time data transmission and device configuration data transmission and so on.In order to make the equipment can achieve the function of CANopen communication quickly,then embedded CANopen module arises.This module owns biggest feature is small in size.Easy to directly be embedded in the user's PCB,and integrates the complete CANopen protocol stack,able to quickly and steadily accomplish CANopen communication.This paper introduces CAN and CANopen protocol in detail,and makes deep research in protocol stack implementation.Based on CANopen protocol communication,slave node I/O module design integrates 8 digital signal input,8 digital signal output,8 analog signal input,4 PWM wave output,real-time feedback the input and output status of slave node I/O module through CAN bus communication.Hardware architecture apply Cotex-M4 K60 chip as the central processing unit,apply TJA1050 chip as the CAN bus communication transceiver,use the KEIL software as the integrated environment of coding,program the imbedded CAN communication driver code base on MCU application manual.Combined with own actual situation to write out the code about object dictionary,PDO,SDO,LLS,heartbeat mechanism and so on,to achieve CANopen protocol implementation.Slave node I/O module is designed for 40 dual-in-line pins,small size and easy to extend.