DP83822I: DP83822 Configuration for 100Mbps Fiber support

user3510003

Part Number: DP83822I

We are using DP83822 (single port 10/100 Mbps Ethernet PHY Transceiver) connected to PowerPC Processor MPC8360 in one of our designs. The electrical interface (RJ-45) is tested and is working fine. We have made necessary Hardware modifications to connect to the Fiber Interface. But we are facing issues while configuring the Fiber interface (100 Base-FX, Full-duplex). We are connecting it to a 1Gbps Ethernet tester through SFP. The ping is not working. Attached Schematic pages (Electrical interface & Fiber interface separately after modifications).

ADTL_SCH_Query_DP83822_FX.pdf ADTL_SCH_Query_DP83822_TX.pdf

over 5 years ago

0 Ross Pimentel over 5 years ago

TI__Mastermind 23675 points

Can you send me the part number of the SFP you are using?

0 user3510003 over 5 years ago in reply to Ross Pimentel

Prodigy 40 points

We are using SFP from Finisar make P/N: FTLF1321P1BTL.

0 Ross Pimentel over 5 years ago in reply to user3510003

TI__Mastermind 23675 points

The transceiver you are using is rated for 1000BASE-LX. The 822 requires 100BASE-FX SFPs. Here is one example of a Finisar 100BASE-FX SFP: FTLF1217P2xTL.

0 user3510003 over 5 years ago in reply to Ross Pimentel

Prodigy 40 points

We are yet to procure the 100BASE-FX SFP as suggested by you.
We tried testing using the SFPs we have currently namely SFP-FE-LX-SM1310 (Cisco make) and SFP-OC3-IR1 (Cisco make). We observed that the link speed is not 100Mbps, it is still showing 10Mbps only. Apart from the hardware modifications, do we need to need to modify anything in software (driver)??
One more observation: When we connected the Finisar SFP FTLF1321P1BTL, in Ethernet tester we could see "ALL SUMMARY OK" but the ping isn't working.

0 Ross Pimentel over 5 years ago in reply to user3510003

TI__Mastermind 23675 points

To enable 100BASE-FX operation, all you need to do is set the bootstrap for 100BASE-FX operation.
You can verify by reading register 0xA, bit[14].

0 user3510003 over 5 years ago in reply to Ross Pimentel

Prodigy 40 points

We have set the bootstrap for 100BASE-FX operation and connected 100BASE-FX SFP Transceiver. We are able to read the bit[14] of Register CR2 (0xA) as "1". We could see "ALL SUMMARY OK" using the JDSU Ethernet tester and also the ping was successful without any packet loss after assembling the LVPECL termination discretes. Although we observed it is not consistent. When we tried to power it on and test after sometime, the DP83822 ethernet interface shows 10Mbps only, while the DP83822 TX CLK shows 71MHz frequency (unlike in the 100Mbps configuration)!

0 Ross Pimentel over 5 years ago in reply to user3510003

TI__Mastermind 23675 points

Does the SFP you are using require LVPECL termination?
The DP83822IF is an CML design and is not LVPECL. Please confirm that you are using 50 ohm termination to AVD for the DP83822IF side.
Are you using 0.1uF DC blocking caps between the SFP and the PHY?
When you boot into a mode with the incorrect frequency, can you check register 0x17 to make sure you are using the correct MAC and clock configuration?

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DP83822I: DP83822 Configuration for 100Mbps Fiber support