Ethernet bring up with RMII

[yulianmatev]

Hello,

I am using X-MPC574XG-MB development board together with MPC5748G
and am trying to bring up the Ethernet module

I was able to send and receive data using the MII interface but when I try to do so via RMII I have no success.

Differences in my configuration between RMII and MII are as follows:

1. On mother board: Jumper J7 is switched to position 2-3 so RMII Clock (50MHz) is enabled
2. On mother board: Jumper J5 is switched to position 2-3 for RMII as initial configuration.
3. Configuration for PHY device DP83848-EP: Register RBR (RMII and Bypass Register) is set to RMII_MODE = 1 (Reduced MII Mode)
   (It seems that point 2 already covers 3, found during debugging)
4. Configuration of MPC5748G: Register Receive Control Register (ENET0_RCR) is configured as: RMII_MODE = 1 (MAC configured for RMII operation.) this goes together with
   MII_MODE = 1 (MII or RMII mode, as indicated by the RMII_MODE field)
   (MII_MODE = 1 is also set for the MII configuration)

Configuration of all RMII ports is kept the same as it was inside the MII configuration.

I am able to access data from PHY registers and they report that link status is OK,

but I am not able to see any data received or sent by the PHY device.

Do you have any ideas what else I have to configure?

[medhedibasly]

Hello,

I'm having the same Issue with RMII Mode, i work with MPC5746C and MPC5748G-MB EVB, i configured the PHY and the ENET controller for RMII mode as indicated in this question which looks correct. is there any other configuration to do?
To test the Communication i use Wireshark and the PC. i think this is not a good way to test the communication.

Peter, by "I uses external loop-back Ethernet cable" do you mean this ?

Regards,

[PetrS]

Hi,

I tested simple external loop-back and I was able to send/receive frames. I have the same jumper setting. Moreover J6 should be removed, but works with jumper placed too.

Do you have PG1 pin still configured for TXD_CLK/RMII_CLK in RMII mode too?

BR, Petr

[yulianmatev]

Hello Petr,

Thank you for your reply!

Yes I do have PG1 pin still configured for TXD_CLK/RMII in RMII mode.

Do you see an issue in that? Unfortunately this week I am not in the office and I cannot try your hint (without PG1 - if get it right)

Best regards,

Yulian

[PetrS]

Hi,

I meant the PG1 must be configured as input still.

Attached is the example I tested. I uses external loop-back Ethernet cable. The TX/RX work in both MII and RMII modes.

BR, Petr 

[yulianmatev]

I was able to compile above ghs project in both cases:
    1. For RMII mode: #define    MII_MODE 0 (inside "main.c")
    2. For MII mode: #define    MII_MODE 1 (inside "main.c")
When I run produced .elf files on target I am able to see that MII configuration produces a frame (source_mac: 00:cf:52:82:c3:01 dest_mac: Dell_3b:33:d0) on Ethernet, but the RMII configuration does not produce any frames.
(Instead of loop-back Ethernet cable I am using normal cable and Wireshark on PC)
Do I need to do some additional confifuration for RMII mode (other than jumper configuration and MII_MODE in "main.c") ?
Could you please compile for RMII mode and attach produced .elf file?

This is my jumpers configuration:

Best regards,
Yulian