PCIe (any version), usb 2.0 bridge ICs - Page 1
Forum section: electronics / projects

author: lk
author_rank: Regular Contributor
timestamp: October 31, 2017, 06:21:09 pm
content: Greetings,I was planning to make my own PCI to USB adapter card, and naive as i was i just expected the bridge chips to be readily available. The only ones i found are 10 USD and up, and as i expect to fail several times before i make this work. I would like something that is cheaper. Does anyone know of an IC that might fit these requirements?I plan to hand solder it, so a package with leads would be appreciated.I have looked at asix, Diodes Inc and TI parts, all very expensive.Does anyone know of a chip that might work, i was surprised that the choices on digikey were so limited.brLasse

author: Monkeh
author_rank: Super Contributor
timestamp: October 31, 2017, 06:50:16 pm
content: I assume what you mean is a USB host controller. These are indeed not readily available, and it's going to cost you a lot more than just finding a card.

author: photon
author_rank: Frequent Contributor
timestamp: October 31, 2017, 07:31:48 pm
content: Hi,For PCI to USB2 check out the PLX (now Broadcom) part for $15.50 at Digikey.Manufacturer Part NumberUSB2380-AB25NI GDescription IC CONTROLLER PCI USB 2.0 88QFNFor PCIe to USB2 check out the PLX part below for $19.32:Manufacturer Part NumberUSB3380-AB50NI GDescription IC CONTROLLER PCI USB 2.0 88QFNThe above are USB endpoint controllers.For USB host controllers the silicon is a lot cheaper. Check out the Microchip part below for $1.30 at Digikey.Manufacturer Part NumberUSB3300-EZKDescription IC USB HOST/OTG PHY ULPI 32-QFNNote that Microchip stole the PLX part number.

author: photon
author_rank: Frequent Contributor
timestamp: October 31, 2017, 08:05:07 pm
content: The ASM1042 is a USB host controller. Not on Digikey but I find it on ebay for $4.38.https://www.ebay.com/itm/ASMEDIA-ASM1042-ASM-1042-QFN-64-IC-Chip-ASMT-USB-3-0-Extension/331728447596?hash=item4d3c8e686c:g:EJwAAOSwPcVVgn1~The best I can tell, the ASM USB device controllers are SATA to USB.

author: Monkeh
author_rank: Super Contributor
timestamp: October 31, 2017, 08:06:53 pm
content: Quote from: photon on October 31, 2017, 07:31:48 pmThat is.. not a host controller. That's a PHY.

author: lk
author_rank: Regular Contributor
timestamp: October 31, 2017, 08:08:40 pm
content: thanks everyonelooks like the asmedia that blueskull suggested has the right price level, so i can afford breaking several of themNow i just need to find the datasheet.http://www.asmedia.com.tw/eng/e_show_products.php?item=150&cate_index=116

author: photon
author_rank: Frequent Contributor
timestamp: October 31, 2017, 08:24:59 pm
content: Yes, you are right. The Microchip part is just the USB PHY and with no logic related to PCIe. If you want a full stack USB host to plug into the PCIe slot of a Windows or Linux PC, the cheapest silicon I can find is the $4.38 ASM1042 on ebay. The TI parts are about twice that. For the USB device controller, the only PCIe to USB device controller I can find on the Market is the PLX (Broadcom) part (which is probably why they charge so much for it). FTDI has some USB device controllers for ~$4, but they are UART to USB or SPI to USB.Also, Monkeh's comment about the final cost being more than the silicon cost is valid because of the requirement of the PCIe driver. ASMedia has a free driver, but it is most likely specific to their board and without sources. If it works you will not be able to modify it. If it doesn't work you will need to become a PCIe driver expert and write one.If this is a project where you are trying to learn what it takes to build a PCIe device to USB host controller, I would suggest a Xilinx Kintex 7 board with PCIe connector. These are not cheap but you have free Xilinx PCIe and USB IP and drivers when you buy a Vivado license. Also you have all the sources and visibility so you can learn and modify it. As Monkeh mentions, the engineering here is not trivial and will cost you more than a few dollars. Over time this price will be minimized to it's lowest manufacturable cost given market demand for it.My observation about standard product ASICs is that you must use them as the vendor intends. I am not aware of any ASIC vendor that gives away the sources to their PCIe drivers, though if you buy enough parts from them they might. The driver is part of the vendor's NRE just as the cost to fab the silicon is.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 01, 2017, 03:14:00 am
content: I don't see much reason to develop your own PCIe USB host card when there are loads of good ones for about $10. Something that would be far more interesting would be a PCIe USB device card, so that a PC can emulate various USB devices - basically when you want something with USB device that is more powerful than a Beaglebone Black or Raspberry Pi Zero.

author: lk
author_rank: Regular Contributor
timestamp: November 01, 2017, 01:06:41 pm
content: Hi NiHaoMike,there are many reason, maybe i do it for learning. Maybe i need to plug many microcontrollers boards into one PC and i dont want the wires. However, i would be interested in the ICs on the 10USD adapters you talk about.-lasse

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 01, 2017, 02:42:15 pm
content: This one uses a NEC chipset:https://www.newegg.com/Product/Product.aspx?Item=9SIA67049F0952I would forget about trying to DIY one unless you really know how to design a PCB for high frequencies. PCIe has a working frequency well into the GHz.

author: macboy
author_rank: Super Contributor
timestamp: November 02, 2017, 03:11:53 pm
content: Quote from: NiHaoMike on November 01, 2017, 02:42:15 pmNot knowing high frequency PCB design has never stopped the guys who are making those cheap boards. I have one particularly bad PCI to SATA controller at home where one channel has a choice of either internal or external connector. They just split the SATA signals and wired them to both connectors, resulting in a 3 cm or so stub no matter which connector was used! With 1.5 Gbps signals!No wonder it never worked well.

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: May 27, 2019, 07:10:37 pm
content: Hey, sorry for digging out this ancient thread. I am searching for something like this for a hobby project right now and wasn't very successfull. Has somebody found more chips until now?I basically want something, that allows me to stick a single USB Device directly into the PCIe Bus. So a single channel PCIe to USB converter. The goal is to connect one of TIs nice USB Sound Card Chips using PCI-express. I basically want to build my very own audiophool pci-e soundcard. Since I don't know anything about the digital part of this hole idea I am looking for a simplest solution with premade drivers that just works plug and play.Is there something in existence that works like that? The price for this chip isn't really a problem since I just want to build this thing for fun.

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 27, 2019, 10:12:19 pm
content: Quote from: Ysjoelfir on May 27, 2019, 07:10:37 pmSounds like a solution looking for a problem. I can't think of any machine that has PCIe but not USB.Just get a PCIe USB card, desolder one of the USB sockets, and build your sound card on that. But why not make a S/PDIF or HDMI connected unit instead? (In the latter case, buy a HDMI audio extractor and replace the DAC in it with a better one.)

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: May 28, 2019, 07:22:05 am
content: Part of the Challenge I put myself on is the Pci-e Connection. Sure, I could just repurpose an usb expander, but where is the fun in that?