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Petrak,
That will work fine unless you're doing realtime processing and using Ethernet too. Reading the PHY like this stalls the NIOS II interrupt response for a significant time period. I know this because it affected my project. When I reported this to Altera the response was "this is how it works". While the PHY shifts in serial data on this MDIO read, the NIOS II will not respond to interrupt requests. We used logic in the Cyclone to delay the task the interrupt was performing to hide this latency that the PHY causes. It was a real pain but we have to respond to an external interrupt within a few uS. Fortunately there was a workaround or our product would have been dead. The MDIO read was causing additional interrupt latency from 31 to 48uS over normal latency times.
Bill A.
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I assumed that this will cause something like this. Interrupts you are talking about are all interrupts in system ? During the read from PHY all interrupts will be delayed ?
For us this is not big issue, we don't have such realtime processing.
So for Altera devices there is no ("right") way to handle info about link state from PHY without this issues ? :(
Thanks
Honored Contributor
