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Altera_Forum
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16 years ago

Altera Ethernet MAC - TX Overflow at ST interface

Hi, I am using the 10/100/1000Mbps TSE from Altera and have some problems when I provide a burst of data to the TSE through the Avalon ST interface. What I see is this: The packets are...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Hi,

I discovered a problem with the tx_almost_full setting of the TSE.

This value is related to the Ready Latency of the Avlon Streaming Interface, which is set to 0. According to the user guide the tx_almost_full must be set to 3.

I was not aware of this requirement and still can not udnerstand why the threshold is linked to the Ready Latency. In the design the tx_almost_full was set to 8 and I though the TSE should deassert its READY when there are at most 8 words of free space ...

When I set the tx_almost_full to 3, which matches with the READ Latency of 0 everything work according my expectation. So, the final question is, why is the tx_almost_full setting linked to the READY Latency ?

Bye,

Bert