4 ms·
Yes. Every lane has 4 data pins. TX+, TX-, RX+, RX- The data is transmitted and received as differential pairs because this helps in signal integrity issues.
by lizknope 5y ago
Yes. Every lane has 4 data pins. TX+, TX-, RX+, RX-
The data is transmitted and received as differential pairs because this helps in signal integrity issues.
You are also correct that you can transmit and receive at the same time but whether this helps our now depends on what you are running.
The Serdes used for PCI-E are also used for other protocols like SATA and USB3. They are extremely similar at the physical layer but the higher layer protocols are very different.
USB 1/2 has a single differential pair so you can only transmit or receive but not at the same time.
USB 3 has differential pairs for RX and TX so you can do both at the same time.
- jlokier 5y ago> USB 1/2 has a single differential pair so you can only transmit or receive but not at the same time > > USB 3 has differential pairs for RX and TX so you can do both at the same time. Just in case this leaves some readers thinking it's only possible to transmit or receive on a differential pair, not so: Copper gigabit ethernet (1000Base-T) transmits and receives at the same time over all four differential pairs, using adaptive equalisation and echo cancellation to separate the outgoing and incoming signals on each pair. The signal processing is quite power hungry, and doesn't work so well at higher speeds. So it makes sense that PCIe wouldn't do this.