Real-time control technologies meet the demands of real-time industrial communications - Part 2

fish001

Real-time control technologies meet the demands of real-time industrial communications - Part 2 [Copy link]

Market opportunities for EtherCAT slave stack solutions for C2000 microcontrollers (MCUs) and a three-stage guide to quickly get started with slave stack development.

In addition to these three aspects of the development process, what other measures did TI take to make our solution more attractive than the traditional stack porting solution? First, we applied our knowledge of the C28 CPU architecture and adjusted the relevant software to better utilize the CPU's capabilities. For example, we optimized interrupt handling, direct memory access (DMA), and control (pulse width modulation [PWM]) synchronization routines to fully utilize the on-chip hardware. In addition, we worked with Beckhoff to update/enhance the released stack to support data processing, making it more suitable for the C28 CPU.

Speaking of working with Beckhoff, the C28 slave stack and hardware abstraction layer (HAL) supporting both serial peripheral interface (SPI) and parallel (external memory interface [EMIF]) communications are used as part of their Slave Stack Configuration tool (SSC). Based on previous C2000 MCU experience, you will find the reference software solution version "Plugfest-ready."

Support for both SPI and EMIF hardware interfaces provides implementation options that allow the system to trade off printed circuit board (PCB) routing complexity with the lowest latency communication. In addition, while the release is tested directly with the Beckhoff ET1100 device, you can adapt the SPI and EMIF HAL drivers to support other EtherCAT slave device silicon solutions, including TI's AMIC110 SoC (SPI - please contact the Sitara forum) or field programmable gate array (FPGA) instances of slave hardware (EMIF or SPI), such as the Beckhoff ET1816.

There is no difference between the EtherCAT slave stack code and application code in the SPI and EMIF processor data interface (PDI), only the device name and product code are different, so SPI and EMIF slave nodes may differ even if they are in the same network. EMIF slave nodes may differ when they are in the same network.

The C2000 MCU feature of the TI EtherCAT software package is the Echoback application example. Although the application demonstration is not complex, it simply echoes the slave node output data structure back to the input, which can be viewed using any EtherCAT master or TwinCAT master. For more information, visit the " EtherCAT Solution Reference Guide ".

By including the Echoback application, TI demonstrates an example of basic use of the stack software and provides you with a placeholder for creating your own applications. Following the Echoback example will make it easier to take advantage of the many optimizations TI has made to the stack and HAL software modules, and provides a good example of an EtherCAT Slave Information (ESI) file. In addition, Echoback has been included in the Quick Evaluation Binary Project.

查看详情

Figure 1: TMDSECATNCD379 EtherCAT board image

Finally, as shown in Figure 1, the EtherCAT controlCARD hardware platform leverages the common 180-pin interface of other C2000 MCU control cards. The EtherCAT controlCARD is physically compatible with any 180-pin C2000 application evaluation module (EVM) or docking station, so EtherCAT connectivity can be added to many existing real-time control application examples. For example, you can use the EtherCAT controlCARD with the Industrial Drive Development Kit (IDDK) to add real-time connectivity to servos using fast current loop and/or position manager technology.

It is also worth mentioning that the EtherCAT controlCARD can operate independently. The hardware is powered using a Micro USB cable, without the need for a docking station or EVM power supply. For more information, see the " TMDSECATCNCD379D EtherCAT Solution Reference Guide ". This helps reduce hardware complexity in multi-node network testing and configuration.