Hello,
We are trying to design industrial network motion controller based on AM3359 and PLCopen Software on Linux.
We have some question about EtherCAT implementation as follows:
(1) Is it possible to implement EtherCAT master/slave with ehternet periperals like TMDXIDK3359 design?
This TMDXIDK3359 board do not use the PR1_MIIx interface. but the TMDXICE3359 design use the PRU1_MIIx interface.
(2) If the TMDXICE3359 design is best for EtherCAT implementation, how can i use the GPMC_A16 ~ GPMC_A21?
(3) Is it possible to control ethernet periperals over PRU?
(4) Is it possible to use two ethernet periperals for general TCP/IP and two PRU_MIIx for EtherCAT master/slave at same time?
Thanks.
1. Yes, it is possible to implement EtherCAT master using the MII interfaces from the CPGSW (gigabit switch). And EtherCAT slave is possible on MII interfaces from the PRUs. Reason we do not recommend doing EtherCAT master on PRU MII is because the firmware support is not there and it is easier to do this using the other MII interfaces available from the embedded Ethernet switch in AM335x. Details on Ethernet switch are in AM335x Technical Reference Manual.
2. Please see an errata published on the http://www.ti.com/tool/tmdxice3359 page. Also, please refer to latest version of TRM for GPMC connectivity in 16-bit Address/Data Multiple mode. The lines GPMC_A1/2/3/4 etc. have to be used to get high address signals. With current ICE and AM3359, it is not possible due to the issues mentioned in the Errata.
3. Yes. But do you mean run classic/traditional IEEE802.3 compliant Ethernet on PRU? It is possible but not a implemented feature in PRU at present. Please use the Ethernet port from the embedded switch for this purpose. On PRU, we support EtherCAT today. Few additional protocols are coming in next 6-8 weeks.
4. Given the allocation of pins, either 2 PRU MII ports and 1 switch MII port or 1 PRU MII port and 2 switch ports are available at any given time. This is due to overlaying of signals for various interfaces onto same physical pins. So, based on pin-multiplex configuration, it is possible to only get certain feature at a time. So, you could do EtherCAT slave on PRU MIIs at the same time as you do EtherCAT master on ONE MII port of the switch. I am not sure if you are looking for EtherCAT master with dual MIIs or single MIIs.