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

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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.

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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