This is commonly used if the space, or cooling is at a premium - the devices became very popular in the cryptocurrency mining world, and I've got a few handy. This device serves a very simple purpose - allows one to extend the PCI Express bus, and install a device away from a motherboard.

Lane 0 Receive - The HSIp(0)/HSIn(0) pair conveys the responses from the device (and interrupts, if there are any).

Lane 0 Transmit - The HSOp(0)/HSOn(0) pair conveys the data (and management information) from the host to the device.

Reference Clock - the REFCLK+/REFCLK- pair conveys the clocking information for the bus - from the host to the device.

In fact, the entire 'data' portion of this hack is done with 6 wires - 3 differential pair. PCI Express is a serial bus - which lends itself to relatively few wires. If possible, I'd have wanted to retain the capacitors to the right of VL805 - the next attempt would be much simpler if they were intact.

The crocked oscillator above the VL805 serves as the clock for VL805 only - I did end up removing it entirely, but it's not strictly necessary. The desoldering is pretty simple - except that the chip has a massive ground pad, which is connected straight to the ground plane of the Raspberry Pi - it required some work with the hot air gun to get it off the board, and I managed to ruin some of the surrounding components. That said, these are sufficiently similar to risk ruining the boards over - and with the visual confirmation over the 3 differential pairs of PCI Express x1 - let's desolder. Unfortunately, there is no documentation for the VL805 chip online - only it's bigger (88-pin) cousin VL800. So, without further ado, the sacrificial goat. Most importantly for our purposes, the USB 3.0 (and 2.0) chip is attached via the PCI Express interface - that means, if we were to remove it, we can gain access to the underlying bus. Pi4 introduces 4GB RAM, USB 3.0 and Gigabit Ethernet. Although Pi3 introduced 64bit capability, it's been pretty limited in practice due to lack of memory. Without much exaggeration, the new Raspberry Pi is likely the largest single-step improvement on the Pi family since the early changes of the form factor.

Connecting external PCI Express devices to Raspberry Pi 4 B+ - since this is the first Raspberry Pi with proper PCI Express interface, it begged to be attempted.Īfter the daily dose of Hackaday - and with an idea that seemed very doable, and actually, with some improvements can be easily reproducible.

Install usb 3.0 pci express card for vr