The AM335x is a set a several devices available in different packages and range of functional capabilities and speed grades. For industrial automation using the PRU based communications, the AM3356, AM3357, AM3358 and AM3359 are the key devices. Among these, only the AM3357 and AM3359 devices have specific hardware support to enable EtherCAT. For additional details on specific differences, please refer to the AM335x product pages on TI.com.