LFPS Detect

Zynq UltraScale+ Device Technical Reference Manual (UG1085)

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2.4 English

The LFPS block is used to detect low frequency periodic signaling (LFPS) in the USB 3.0 protocol. It compares the magnitude of differential signals on the PS_MGTRRX pins with a specified reference and provides an output to the PCS. This output is asserted in the presence of an LFPS signal greater than 300 mVPPD and deasserted in the presence of any signal less than 100 mVPPD. The reference of comparison is programmable from 100 to 200 mVPPD. The output is deasserted during reception of valid super-speed (SS) data but it can glitch because of high-frequency components in the data. A programmable digital filter is implemented in PCS to filter out such unwanted glitches.