DP83822IF: The SD polarity of DP83822IF

user5209515

Part Number: DP83822IF
Other Parts Discussed in Thread: DP83822EVM

Hi Ti friends,

We are using DP83822IF in our design, it is working in RMII mode , I still confused about the signal detection polarity, because I set RX_ER bootstrap in mode 1, the following datasheet says signal detection is active low.

but we have read register 0x0465, the value is 0xff00 , that is to say, signal detection polarity is active high , we haven't configure the register in our code, why the value of signal detection polarity is not the default active low, is the bootstrap setting matching the value of register 0x0465.

another question i want to ask ,can I disconnect SD pin between DP83822 and SFP in our design ?, can you send me some reference design of DP83822 working in 100M-FX mode, thanks

over 5 years ago

0 Aniruddha Khadye over 5 years ago

TI__Mastermind 18425 points

HI user5209515,

I believe there is a typo in register description of 0x465. The signal detect is active low by default. I will recommend connect SD signal from Fiber transceiver to DP83822 (LED_1) and enabling signal detection by setting RX_ER to mode 4. The DP83822EVM has a example connection for SFP fiber transceiver with DP83822 PHY.

-Regards,
Aniruddha

0 user5209515 over 5 years ago in reply to Aniruddha Khadye

Prodigy 150 points

Sorry, I have set RX_ER to mode 4, I read the value of register BMSR(0x0001), the value of link status bit is no link; when I set it to mode 1, the link status is OK.

0 user5209515 over 5 years ago in reply to Aniruddha Khadye

Prodigy 150 points

Sorry, I have set RX_ER to mode 4, I read the value of register BMSR(0x0001), the value of link status bit is no link; when I set it to mode 1, the link status is OK.

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DP83822IF: The SD polarity of DP83822IF