DP83867IRPAP-EVM: 100 Mbps Link up issues and data could not received on MAC

Thank you Geet for replying.

1. Is PC also configured for 100M Force Mode ? After disabling Auto-Neg on DP83867, you will need to trigger soft reset.
Hardik: I tried soft reset, but there are no attempt to establish the link.
Is there any sequence recommended to initialise PHY? For example: First MDI relevant configurations, then MII relevant configurations etc..

following is the sequence I am using:
1) 0x1F = 0x8000 /** Hard Reset */
/** Wait here for a while */
2) 0x0D = 0x001F
0x0E = 0x0031
0x0D = 0x401F
0x0E = (u32ReadData & 0x7F) /** Clear bit 7 of Configuration 4 register to configure strap RX_CTL; u32ReadData holds value stored @0x31 */ /** I decided to do this because no strap configuration on RX_CTRL and information from section 8.5.1 NOTE section */

3) 0x00 = 0x2100 /** 100 Mbps, Full Duplex and Auto Negotiation OFF */
4) 0x1F = 0x4000 /** As you recommended */
/* I halt my debug session here, just to see if Link establishes and PC sends any data on the bus, but nothing happens. It remains disconnected */
5) 0x0D = 0x001F
0x0E = 0x0032
0x0D = 0x401F
0x0E = 0x0000 /** Disable RGMII */

Do you see any error in sequence or any suggestions?

3. You may need to play with skew control between data and clock for RGMII. Refer to register 0x0032 and 0x0086.
Hardik: I am using MII interface and RGMII is also disabled correctly through Extended Addressing method.

Thank you for your support!
Hardik

Hi Hardik,

Configuration to force 100M Force mode looks ok. Questions:

1. If you enable Auto-Negotiation, does device links up ?

2. Have you ensured PC is in force 100M mode as well ? Can you try connecting this to other device and ensure 100M force is supported by PC.

BTW, why you want to force 100M, instead not use Auto-Neg ?

Regards,
Geet

Hi Geet,

1. If you enable Auto-Negotiation, does device links up ?

Hardik: Yes, it does. But Transmit from PHY to PC does not work. Receive works fine. 

2. Have you ensured PC is in force 100M mode as well ?

Hardik: Yes, in configuration settings, port is set to 100 Mbps Full Duplex. 

Can you try connecting this to other device and ensure 100M force is supported by PC.

Hardik: I will try and let you know. 

Meanwhile I tried other device with my FPGA, and link did come up with the same startup routine. However, Transmit is still not working. Could you please look into my schematics, is there anything wrong I am doing? I tried to look into one of the debug guideline available only on TI website, and values are as recommended. Could you please double check and provide your comments? 

 

BTW, why you want to force 100M, instead not use Auto-Neg ?

Hardik: While starting up application it is required to have knowledge of link speed to allocate memory and for scheduling tasks to work incoming frames. In most of the cases, link speed is predefined. In short, to have more deterministic application with limited internal resources it is must in many applications to force link speed. 

Thank you,

Hardik 

Hi Hardik,


On Forced 100M link, you tried DP83867 based FPGA with other device in 100M force mode and link is happending ? Correct.

Now only issue you have is Transmit data from your FPGA/PHY does not go out properly to PC.

I suspect your MAC interface is not tuned properly. Typically to isolate the issue, suggest you try following loopback:

1. MAC loopback:
2. Reverse loopback.

Regards,
Geet