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Altera_Forum
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15 years ago

Acessing Data on GMII

Hi folks, at the moment i am planning the architecture of the project of my final thesis. I want to implement a Timestamping-Unit(TSU) for the PTP-Protokoll (IEEE1588). The ptp i want to set...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

I am very sorry to respond only now, but i was away for the last 3 days.

Hm maybe my understanding isn't right,please correct me if i am wrong.

In my opinion i have to change the timestamp only in the Sync-packet if the device acts as master and sending this sync packet. If i timestamp it at NIOSII i got an jitter in the delay ? For most accuracy i have to stamp it near the line.

I agree with you Daixiwen, that i only have to timestamp the incomming of packets (there are no need of modification in the packet). But at sending the tsu have to modify the timestamp and CRC packets. Do I miss a point ?

But back to my main question; do u have any examples of accessing the gmii or is it really as easy as i think it is. And the second question how to u deliver the timestamps to nios ? Through a memory fifo or via attaching the timestamp to the pakets.

best regards