• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 46 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DP83848I: DP83848I

yu hai
Prodigy 20 points
Part Number: DP83848I

Tool/software:

Hi  SIR

            Currently, we are using the DP83848I PHY chip and want to disable the MDIX function through the register. According to the manual, setting bit 15 of 0X19 to 0( disable MDIX EN), but the verification was unsuccessful. Additionally, do we need to set bit 14 of 0X19 to 1? Or are there other registers that need to be configured?

TKS

  • 0
    TI__Guru**** 176811 points

    TKS

    When enabled, this function uses Auto-Negotiation to determine the proper configuration for transmission and reception of data and subsequently selects the appropriate MDI pair for MDI/MDIX operation. The function uses a random seed to control switching of the crossover circuitry. This implementation complies with the corresponding IEEE 802.3 Auto-Negotiation and Crossover Specifications.

    So if you set bit 15 of register 0x19 to 0, you are disabling the AUTO_MDIX function. And you have to manually set or clear bit 14 of register 0x19 depends on whether you are using a straight or a crossover Ethernet cable.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 20 points

    tks，After setting BIT15 of 0X19 to 0, when reading the status register of 0X10, get value as 0XFFFF. May I ask why this would cause such a problem?

  • 0 in reply to yu hai
    TI__Guru**** 176811 points

    Hi,

    Reading 0xFFFF is not the expected behavior. Can you please read register 0x02 and 0x03? These two are read-only registers and should return valid data. If you are still reading 0xFFFF, then we may need to look at the DP83848I power-up sequence. 

    Thanks

    David