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Altera_Forum's avatar
Altera_Forum
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14 years ago

Connecting two Marvell PHY devices to one Cyclone III FPGA

Hi,

- We need to send data from one Cyclone III development board to two receivers. One of these receivers is a displaying panel while the other one is sent to another cyclone III development board (that is connected to a displaying panel too).

- This is implemented as shown in the attached image, by branching the required signals like mdio, mdc,data,.. .

When assigning the mdio to two pins one of them is D2 in bank 1 and the other one is the already assigned pin in cyclone III development board (AB2) "PHY not found in PHY profile" error occurred. If changing the pin location to IOBANK_1 , the connection is successfully established & there is no error detected.

Kindly note that this error occurred without connecting the second board?

Can any one help us.

Thanks & Regards

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    Why do you use two extra pins? Both PHYs can be connected to the same MDC/MDIO lines.

    Anyway I think your problem is with ORing the mdio_in signals. A non driven mdio line will pull to a high level, then the OR gate will always result in receiving all ones.

    Replace OR with AND.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    14 years ago

    --- Quote Start ---

    Why do you use two extra pins? Both PHYs can be connected to the same MDC/MDIO lines.

    Anyway I think your problem is with ORing the mdio_in signals. A non driven mdio line will pull to a high level, then the OR gate will always result in receiving all ones.

    Replace OR with AND.

    --- Quote End ---

    Thank you very much for your reply :)

    1- We use extra pins to connect to another PHY that is not existing in Cyclone III development board. These pins are connected to the second designed board via the HSMC connector

    2- Regarding your suggestion we are going to replace the Or gate with an AND one.

    Kind Regards