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Pragya's avatar
Pragya
Icon for New Contributor rankNew Contributor
4 months ago

Query regarding accessing marvell phy device (88e1111) through i2c

I'm using Stratix 10M board, we are trying to access marvell phy device 88e1111 through i2c. We want 100mbps SGMII with autoneg disabled. This is the sequence that I've tried :

  • Write 2100 to reg 0 ( 0010 0001 0000 0000) : Copper full duplex and speed 100mbps, auto neg disabled)
  • Write 0400 to reg 9 (0000 0100 0000 0000) : Port type : = Prefer multi-port device (MASTER)
  • Write A100 to reg 0 ( 1010 0001 0000 0000) : Softwrae reset

For this sequence we took this as reference and modified it according to our speed and disabled autoneg : https://community.intel.com/t5/FPGA-Wiki/Marvell-88E1111-PHY-Configuration-Steps/ta-p/735410

When I read back i see the speed did not change and remains at 1000mbps.

We have tried writing directly to reg 0 with speed change along with software reset ( A100) , still we see the speed didnot change.

And also no matter what value I write to HW_CFG_MODE it always reads 0001(resrvd value) even after software reset. Are there any 88E1111-specific registers I should configure for SGMII mode?

Any insights or suggestions would be greatly appreciated. Has anyone successfully configured this PHY via I2C for similar requirements?

3 Replies

  • FvM's avatar
    FvM
    Icon for Super Contributor rankSuper Contributor
    4 months ago
    Hi,
    isn't 88E1111 pin-strapped to MDIO configuration rather than TWSI (I2C) mode?
  • Pragya's avatar
    Pragya
    Icon for New Contributor rankNew Contributor
    4 months ago

    We are using finisar 8251 part, there they have CONFIG6 bit hardwired to 100 to support i2c access. ANd also after writing to the registers, we are getting back the ack signal.