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AM335x PRU - CSPW

Alessio Riccardi
Prodigy 30 points

Other Parts Discussed in Thread: SYSBIOS

HI, I would like to use the AM335x as a ethernet switch with VLAN.

This ARM has an internal switch (CSPW) that should be able to managed the VLAN protocol and has the PRU.

Since I have not found any example that built a switch VLAN on the PRU, I would like to make a HW that, at boot time, set the pins to connect at two external PHY either the switch CPSW or the PRU (for industrial fieldbus).

Is this possible?

In this way, without any external chip, I can managed or a ethernet protocol or industrial fieldbus.

Thanks

Thanks.

  • 0
    TI__Expert 8175 points

    Alessio,

    Are you using an RTOS for this? If so, what version of TI-RTOS are you using? What other TI tools are you using?

    Moses

  • 0 in reply to Moses Isang
    Prodigy 30 points

    Hi Moses,

    I'm doing a preliminary study about the possibility of build a device that should communicate with Fieldbus or Ethernet protocols.

    Sitara supports many fieldbus protocols using the PRU, but unfortunatelly there aren't any Ethernet switch built in the PRU that can supports the VLAN Ethernet packets (this is mantatory for the device that I have to build). For this reason I would use or the CPSW (for Ethernet VLAN communications) or the PRU (for the Fieldbus communications) through the same MII/MIDO interface (to use only two Ethernet sockets).

    If that is possible, I think that I'll use SYSBIOS 6.x.

    Thanks

    Alessio

  • 0 in reply to Alessio Riccardi
    TI__Expert 8175 points

    Alessio,

    I can confirm that you can use SYS/BIOS on the AM355x and NDK supports VLAN. I'll have to route your question to the Sitara Ethernet driver experts to answer the rest.

    Thanks,

    Moses

  • 0
    TI__Expert 7360 points

    Hello,

    To answer your question on using CPSW or PRU at boot time, please refer the ICEv2 schematics. ICEv2 uses an external jumper to identify the interface to be used.

    Regards,
    Vinesh

  • 0 in reply to Vinesh Balan
    Prodigy 30 points

    Hi,

    I look the ICEv2 schematics. In this schematic they can be shown two multiplexer (SN74CBTLV3257RGY) between the external PIN of the MII/RMII interface and a single Ethernet Socket (through the PHY).

    Studying in details this schematics, I found that this multiplexers are used only to exchange the MII/RMII interface (with either PRU and CPSW).

    I would like to build a new device that uses only a specific interface (MII or RMII) between the Sitara end the PHY.

    For this, I think that there are the opportunities to use the PRU or CPSW through the same PIN of the Sitara without any external logic (like the multiplexets) except the PHYs.

    Is this right?

    Second question: Does the CPSW support the 802.1q (VLAN protocol) ?

    Thanks

  • 0 in reply to Alessio Riccardi
    TI__Guru 50931 points

    Hi,

    1. PRU-ICSS only supports MII interface

    2. GMII2 and PR1_MII1 pins are muxed at SOC level and you do not need a h/w mux here

    3. For GMII1 and PR1_MII0 pins, h/w mux is the only option in AM335x

    4. CPSW h/w supports VLAN - (Linux CPSW driver supports 802.1Q not sure about Industrial SDK+NDK)