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Altera_Forum
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17 years ago

ALT2GXB loopback problem

Hi, I'm using an Arria EP1AGX60CF484C6 with an ALT2GXB core configured in XAUI mode (4 lanes). I'm trying to do a loopback to test it out. The loopback is in the core, so what I've done is con...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

Hi,

You reset sequence does not really comply with the handbook. Tx_digitalreset should always really be released first, followed by Rx_analogreset, followed by rx_digitalreset. this is all explained in the handbook and ensures a proper sequence for the Tx and Rx PLLs locking.

You do realise that there is already a loopback function in the ALT2GXB right? OK, so it looks like only the serial loopback is available in the XAUI mode but this could make it simpler for you (depending on what you are trying to do. all you need to do is pump in your data into the Tx_datain along with your tx_ctrlenable signals, then simply assert the rx_serialoopback and your transmitted serial data will be looped back to your Rx_datain. you should be able to observe the same data coming out of the Rx_dataout.

Hope this helps.