The STM32 can communicate with up to 8 PHY chips on a single MII or RMII interface. At power up the PHY sets itself up based on the state of external pins (pulled up or down). After power up they are placed in their normal conditions (either pulled up or down). To keep the design simple we only attach the configuration pull ups or pull downs. As a result we are loading a PHY number of 1. Since we only have one PHY its number is irrelevant as long as we can talk to it. We need to be able to change the PHY number during initialization. Is that a definable variable?
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