I'm looking to create a device that acts as a host to a USB peripheral, format the data, then send it out to another host (the PC). Are on-the-go chips capable of accomplishing this or would you need to implement both a host USB microcontroller and a peripheral USB controller? I don't see much information out there for creating a middleman that performs data molding for USB prior to reaching a host. Any information would be appreciated, hopefully I didn't butcher this concept.
you should use a microcontroller with 2 USB busses.
One should act as a host, and the other as a slave.
You will need to implement them both.
USB OTG is used to create a host and a slave in 1 device with 1 connector,
so it's impossible to use them together at the same time.
Related
I am trying to use the Thrustmaster T-Flight Hotas X joystick with my STM32 f407 Discovery board. As you know, the joystick has a USB connection, but actually I do not know how it transmits data and I do not know what kind of protocol it uses...do you have any advice?
Is there a way to connect the joystick to the board?
Yes, you can use the USB OTG port in host mode to connect your joystick.
The joystick will use USB HID protocol - this is documented in detail at usb.org. Short version: The device tells you in its "report descriptor" how the data is formatted. The data itself is transmitted via interrupt endpoint.
Unfortunately, the software side is non-trivial, as you need host mode on the MCU. Parsing the report descriptor is not required if you only ever use the same joystick model - which can be identified using the VID:PID in the device descriptor.
There should be an appnote with some example code for USB host mode on the STM website, but in order to support your joystick you probably have to make some modifications - which are rather difficult for beginners.
I am new to Wireshark and capturing packets and all Stuff. Let me get it to the straight.
I have a hardware which outputs its data over Ethernet using a UDP Broadcast. I Can directly plug a Ethernet Cable to a In-line RJ-45 Coupler (attached to the hardware) and my PC Running Wireshark.
REQUIREMENTS : I need to Capture RAW Data which my hardware is broadcasting so that it can be given to other team so as to know the format in which it is providing for further post processing.
What I Did : Initially , I connected the Ethernet Cable from my home and Started capturing the packets which didn't make any sense to me.
Can you please point out if I am going in correct direction ? Sorry if its a very basic question, but raw data from the hardware is important for my further tasks....
As far as any software can understand a wire you will always get a packet. Between you (in front of a computer) and the cable in the in the RJ-45 jack sits a NIC (network interface controller, i.e. your network card).
Your Ethernet NIC will read the current on the cable (in manchester encoding for ethernet) and synchronize itself to any Ehternet traffic on that cable. What does "synchronizing" mane in there? In front of any Ehternet traffic come 64 alternate bits of 0s and 1s which are meant to synchronize the clocks on both communicating NICs. Without proper clock synchronization some data may be misinterpreted.
But why I am talking about clock synchronization? Because if you want the data as RAW as it is on the cable you will not get it. A NIC will never send any synchronization bit to the rest of the computer, therefore it is absolutely impossible to read exactly what is on the cable by using software.
On the other hand I find hard to believe you want the RAW data as RAW as that. After the synchronization bits come an Ethernet encapsulated packed. Yup, Ethernet uses packets. They're link layer packets (layer 2 in OSI).
And wireshark gives you exactly that (in most cases, see note at the end for two exceptions to this rule): every Ehternet packet that the NIC understands, manages to sync, and manages to read without collision is sent to the kernel and then read by wireshark. A cable has electrical interference and has no provision against collisions (it's just a piece of cooper!) therefore the NIC abstracts things like interferences and collisions.
I'll repeat it once more: After abstracting the synchronization bits, sender collisions (which turn the cable into one huge interference) and plain interferences; all that remains is a stream of packets, one after the other.
Extra Notes
NICs sometimes do ignore some Ethernet packets: packets that are not directed to their MAC. This can be changed by enabling promiscuous mode (available in most NICs). This is irrelevant for broadcast packets.
There are exception to the rule of wireshark getting all the traffic coming from the NIC:
If the traffic comes incredibly quick, wireshark may drop out of kernel schedule and not see some packets. It happens, nothign can be done about it.
If you listen on all interfaces (as opposed to selecting a single interface to listen at), wireshark will strip the Ethernet (or Wifi) headers. This is a wireshark hack needed to make output files uniform (and possible to be read by other applications).
TL;DR, wireshark output (pcap) is pretty much just the stream of packets that it got from the NIC, one after the other. That is as RAW as you can get with software.
New to VB.NET here.
I was wondering if there is a way to determine if there is something connected to a specific USB port. For example, I noticed that in the Device Manager under Universal Serial Bus controllers, there are Generic USB Hubs. For one of them, the Location is Port_#0001.Hub_#0003.
For what I am doing, I just want to know if something is connected to that specific USB port. It doesn't matter if it is a flash drive, USB HID, or even a microcontroller.
Thanks
I'm developing an embedded USB device which needs to be available to two different hosts.
The first is a normal PC, where it will be used as a MSC (mass storage) device, and the second is a specific hardware which the USB device needs to comunicate with a CDC profile.
during the enumeration, the USB device send descriptor table where it declares its capabilities.
Is there a way in the enumeration process to know to which host the device was connected to ?
The simplest solution perhaps would be to implement a "USB Composite Device", where the single device presented both the MSC and CDC class interfaces simultaneously. The host PC would see both interfaces, but you could simply leave one unused. The "specific hardware" would probably simply ignore the MSC class if it had no support for it.
I'm trying to interface the Mindwave (http://store.neurosky.com/products/mindwave-1) with my Altys board, through the USB UART port. The dongle I'm trying to connect is basically a wireless reciever that outputs serial data stream on the USB connection. I'm trying to read in this serial stream on the FPGA.
The problem I'm seeing is that when I try to Chipscope the UartRx pin (A16), I see no activity on it even though the dongle is supposed to send 0xAA in standby mode.
Since the FPGA does not power the dongle, I have it connected to an external power USB hub and then connect the hub to the FPGA. However I don't see any activity.
Do I need to convert the signals to another level, or invert them? I thought the EXAR chip takes care of it.
Did you try swapping RX and TX?
Did you have acces to a scope? To check you can repeatly send 'U's (0x55) and look with a scope to see which line is RX and which is TX. You can also check the speed of the interface with this method.