/tags/lfps/ Recent content in Lfps on kate's lab notebook Hugo en-us Tue, 01 Sep 2020 11:38:10 -0600 /post/serdes-lfps/ Tue, 01 Sep 2020 11:38:10 -0600 /post/serdes-lfps/ <p>Lately, I&rsquo;ve been developing a USB3 stack, and a USB3 frontend using the ECP5 SerDes. The ECP5 SerDes seems <em>almost</em> perfect for USB3, which shares many of its implementation details with PCIe. However, there are a couple of hitches.</p> <p>The more difficult to deal with is support for USB3&rsquo;s <em>Low Frequency Periodic Signaling (LFPS)</em>. LFPS carries small bursts of information via a slow, out-of-band signal, meant to be used before the high-speed USB3 link is established:</p>