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Altera_Forum's avatar
Altera_Forum
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13 years ago

Transceiver Rate Match FIFO - Why is it needed?

Hi, I've noticed protocols like PCIe include a feature where special "skip" codes are inserted into the data stream so that the receiver can drop or repeat these codes to match the received dat...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

Yes the P in PLL stands for 'phase' but when a PLL locks to the phase of the input, this means it is also frequency locked (see the second paragraph of the Wikipedia PLL article, unfortunately I can't post the link).

Since the Rx-PLL will be frequency locked to the incoming data stream I still don't understand how any slippage/drifting can occur and why the rate-matching FIFO is needed.